© The Authors 2025

1 Introduction

As in any natural science, in meteor astronomy, databases are a fundamental starting point in many detailed studies. Therefore, the high quality of these databases as well as the absence of errors and artefacts are essential for the results of meteor data analyses to come to correct conclusions.

The International Astronomical Union (IAU) Meteor Data Center (MDC) shower database is widely used by the community of meteor astronomers. It has been used in numerous scientific studies with various outcomes, such as identifying the parent bodies of meteoroid streams and analysing their dynamical evolution (e.g. Vaubaillon et al. 2019), predicting meteor shower outbursts (e.g. Egal et al. 2023), and developing models of meteoroid environments near Earth (e.g. Moorhead et al. 2017, 2025). These models are essential for protecting satellites and space detectors and are also used by spacecraft designers and mission planners¹. The MDC maintains an official catalogue where new meteor shower discoveries are submitted to receive a unique designation. However, a single meteor shower may be observed by various teams and/or using different techniques as well as in different years during subsequent encounters of the stream with the Earth. Each submission (a set of mean shower parameters and a set of individual orbits) of the same meteor shower is called a ‘shower solution’, and showers with multiple solutions in the MDC are referred to as ‘multisolution showers’ (MSSs). Showers observed only once and/or submitted by a single team are referred to as single-solution showers (SSSs).

The classification of the observed shower – whether it is a new, uncatalogued shower or a new solution of an already catalogued shower – depends entirely on the subjective approach of the authors submitting their observations to the MDC. This sometimes leads to contamination of the MDC with incorrectly assigned shower solutions. For example, (problem 1) if a new observation of a previously known meteor shower is incorrectly submitted as the discovery of a new shower, a duplicate shower will appear in the MDC. This means that such a solution, instead of forming an MSS, will create a new SSS with a different designation in the MDC. However, the opposite problem occurs (problem 2) if an observed shower is incorrectly submitted as a solution to a catalogued shower it does not belong to. In this case, a false duplicate solution will appear in the MDC. Incorrectly assigned solutions to an MSS shower distorts the shower’s characteristics. In this work, we use the same terminology as in our previous paper Jopek et al. (2024) (hereafter referred to as Paper I), which serves as the initial basis for this study.

Regarding problem (1), in Paper I, we identified seven SSSs as duplicates of previously catalogued showers (listed in Table 7 of Paper I). All of these have already been removed from the MDC Working List. Shower 1196/ZCM, submitted to the MDC in 2022, was also recognized as a duplicate by the authors (Odeh et al. 2023), who, however, did not include its parameters in their final publication as a new solution for its duplicate counterpart, shower 246/AMO. Therefore, it could not be reassigned to that shower in the MDC². The other six showers found to be duplicates in Paper I (i.e. 1151/NPA, 1110/CEP, 1108/IHR, 1157/FCD, 1161/THT, and 1107/JID) were submitted to the MDC in 2022 and likely also recognized as duplicates since they do not appear in the final publication of this submission (Jenniskens 2023). However, under their respective duplicate counterparts, only the 1151/NPA shower solution was found (under shower 575/SAU), with parameters and a mean orbit that exactly matched the submission; therefore, this move was also made in the MDC. In the other cases, the corresponding parameters did not align with the submission, so these solutions will be among the removed showers unless they are resubmitted to the MDC.

As for problem (2), we revealed in Paper I that the IAU MDC meteor shower database contains a considerable number of false duplicates (solutions misclassified as members of the MSS). Showers contaminated with false solutions exhibit biased characteristics that influence the studies that use them. Their presence reduces the quality of the database, so it is desirable to verify and remove or possibly correct misclassified shower solutions. We address these issues in this study, with the aim of restoring the internal consistency of each affected shower. We propose specific solutions for each of the showers requiring reclassification. In doing so, we continue our efforts to improve the content of the MDC database.

2 Input data used

We used the same meteor shower data set as in Paper I (including 920 meteor showers, 252 of them MSSs, as of December 2022), as well as results obtained from it. Our starting point is the list of false duplicates taken from Paper I. We provide this list in Table 1. Its content was obtained using two methods: one involving the use of cluster analysis and orbital similarity function (CAM method), and a second one called ‘maximum-sigmas’ based on a direct comparison of selected geocentric and heliocentric shower parameters (MSM method). Details of these methods are available in Paper I.

In Table 1, for each shower potentially containing false duplicates, the meteor shower codes³, and two values of orbital similarity DH_Min and DH_MI are given. They were calculated using the hybrid D-function (see Jopek 1993; Jopek & Froeschle 1997); the DH_Min is the smallest threshold values of orbital similarity by which all members (all duplicates?) of the given MSS can be identified using the CAM method; DH_MI gives the maximum acceptable threshold value to reliably identify (by applied cluster analysis) a group of the size given in column N_S. The threshold values of DH_MI correspond to the probability of 1% of randomly identifying a group of size N_S, (given in each row of Table 1) in all analysed meteoroid streams orbits. As we see, the size of N_S=2 occurs most frequently, so the corresponding thresholds do not depend on the cluster analysis used. For N_S=2 the threshold DH_MI values depend only on the size and type of orbital sample being tested (short, long orbital period streams). Using formulas (21) and (22) (given in Table 9 in the Jopek & Bronikowska 2017), the plausible threshold values of orbital similarity for pairs of orbits taken from a sample of similar size as used in our study are 0.022–0.025. Therefore, based on a comparison of the DH_Min and DH_MI values, we can claim that all meteor showers in Table 1 contain false duplicates, especially those with N_S=2.

However, the results given in Table 1 are of different status. For example, for the first three streams: 3/SIA, 127/MCA and 321/TCB – the differences between DH_Min and DH_MI are small, and we can attribute their causes to the limitations of the methods used in Paper I. We therefore regard these MSSs as correctly classified in the MDC, and have omitted them from further discussion. In the remainder of this article, we address the causes of all the other possible misclassifications and propose appropriate corrections to the MDC database.

3 Methodology

Searching for duplicates of an already known shower has some analogy with linking observational data of a ‘new’ asteroid with that of an already known object. Unfortunately, because of the low precision of the meteor observations and, above all, the lack of access to the orbital data of the members of the stream, this kind of approach could not be used here. Therefore, in Paper I, in order to verify the status of the members of MSSs among MDC data, a methodology analogous to the searching for streams among observed meteoroids’ orbits was used. Despite the limited methodological rigour, this approach proved to be successful; solutions of almost all major streams as well as many minor streams were confirmed as duplicates; and, on the other hand, the correctness of 56 classifications was questioned; see Table 1.

However, the decision of whether a newly found solution of a meteor shower is the first solution of newly discovered, autonomous shower, which has not been known, or it is another solution belonging to an already known shower, is a complex problem, as differences in solutions may, to some extent, also reflect the actual properties of the stream. In this section, we discuss all possible causes of differences in MSS solutions.

The first issue to consider is the existence of largely structured showers and shower complexes. In more detail, some meteoroid streams have a filamentary structure, and their meteoroids hit Earth, causing showers with very similar mean characteristics. Then, it is possible either to regard these similar showers as the autonomous entities or as the structures of the same showers. Or, some mean parameters (or a single mean parameter) of a group of showers can be consecutive, but extended within a large interval, which is hardly acceptable as the interval of values of single shower. In such a case, we usually speak about the shower complex. Thus, the classification also depends on the convention adopted by the authors, as no document has defined this to date.

Our methodology used in the following regards each shower of a shower complex as the autonomous shower. In addition, if a shower filament can be discerned, it is also regarded as an autonomous shower. (If we always knew the uncertainty of parameter determination, σ, the filament could be discerned by a difference that exceeds 1 σ.)

Another possible cause of false duplicates in MDC is incorrect meteoroid data and thus inconsistencies in their geocentric and heliocentric parameters. In Hajduková et al. (2023), the consistency of the data in the MDC was established with their counterparts in the source publications. The results shown in Table 1 were found using only data that have passed this verification process. Therefore, as the next step, we decided to verify whether the cause of false duplicates in MDC is the lack of internal consistency between averaged geocentric parameters and averaged orbital elements of a shower. For this purpose, we used a software package published by Neslušan et al. (2024). We considered the stream to be biased with incompatibility of the data, if the differences between the catalogue and the recalculated values of even one parameter were: Δα_g ≥ 5.0°, Δδ_g ≥ 2.5°, ΔV_g ≥ 1.5 km s⁻¹, for geocentric parameters, and Δq ≥ 0.05 au, Δe ≥ 0.05 Δω ≥ 5.0°, ΔΩ ≥ 5.0° and Δi ≥ 2.5°, for the orbital elements. Obtained results are discussed in Section 4. All MSSs for which some parameters were found to be internally inconsistent are marked with asterisks in the last column of Table 1.

Other reasons why two sets of averaged parameters for the same meteoroid stream may differ significantly can include the following:

• manual and automatic astrometry of observed meteor images (Koschny et al. 2009),

• the algorithm used to calculate the orbital elements (see e.g. Whipple & Jacchia 1957; Dubiago 1961; Ceplecha 1987; Borovicka 1990; Borovicka et al. 1995; Jopek & Valsecchi 2010; Dmitriev et al. 2015),

• the difference in the epochs of osculation of the orbital elements used to calculate the averaged stream orbits (Williams & Jones 2007),

• the way individual meteoroid data are averaged (see Voloshchuk 1999; Voloshchuk & Kashcheev 1999; Jopek et al. 2006, 2010b).

Meteors are observed with different techniques and reduced in different ways using different astrometric methods. The orbits of the observed meteoroids are calculated in different ways, taking different approximations of Earth’s ephemeris and different timescales. Meteoroid streams are almost always identified among orbits corresponding to different epochs of osculation. Usually these differences are not large, but sometimes they approach 50 years, for example, in the case of the solutions of stream 183/PAU from Table B.1. Using the work of Williams & Jones (2007) it can be estimated that for two averaged orbits of the same stream, corresponding to distant epochs of osculation, and additionally taking into account other factors mentioned above, the values of the hybrid DH-function can be greater than 0.1. That is clearly more than the acceptable threshold values of 0.039–0.059 for the pairs listed in Table 1.

In order to estimate the effect of these factors on the D values between the averaged orbits of the streams more precisely, it is necessary to have access to the parameters of the members of a given stream. Unfortunately, the requirement to include the parameters of the stream members in the MDC together with the averaged parameters of the stream was introduced relatively recently (Jenniskens et al. 2020). Hence, with a few exceptions, this access is not available for the MSSs listed in Table 1. For this reason, in the present study, when analysing the misclassified duplicates in the MDC, we use only data from Tables 1, B.1 and C.1. This means that we could use the positions of the shower radiants on the sky maps, the averaged orbits, the corresponding DH-values, and the contribution of the individual components to the DH-function values. Furthermore, we were able to take into account the links of MSSs with their parent comets, if confirmed or not, as given in Durišová et al. (2024).

4 Discussion of false duplicates

In this section, we analyse each MSS in more detail. In the first Subsection we deal with groups with 3 or 4 members. In the next Subsection we discuss those MSSs for which we had two solutions available in our sample. In the Appendix in Table B.1, the geocentric and heliocentric data of these MSSs are listed. Also in the Appendix in Table C.1, for all pairs of each MSS (see the second column of that table), the DH-values and their four components from the orbital elements of the compared pairs are given.

Basically, based on the high values DH_Min in Table C.1, and in view of the similarity threshold values for pairs of orbits that were adopted in Paper I, (DH_MI = 0.039 for orbits with i ≤ 10°, DH_MI = 0.059 for i > 10°) it can be argued that among the MSSs from Table B.1 there is not a single pair correctly classified. In addition to verification using the D-function, all pairs of solutions in Table C.1 were verified using the MSM (maximum sigma method, see Paper I). In all cases, this verification turned out to be consistent with the result obtained with the D-function. So, on that basis, we could end the discussion.

However, the existence of false duplicates in the MDC is the result of a long-standing subjective approach used to decide whether a new meteoroid data set represents another solution to an already existing stream. Since this decision is complex (as described in the previous section), we still do not have an officially accepted rule on this issue to date. The first MSSs were created in the book by Jenniskens (2006). The author compiled shower solutions from various publications by different research teams using an approach that is, unfortunately, not clearly enough explained in the publication. Showers created in this way were sometimes named after one of their solutions given in the original paper or renamed. The author kindly provided the MDC with the 230 meteor showers published in this book at the time of the creation of the shower database in 2007, see Jopek & Jenniskens (2011). Later, new showers and their solutions were added to the list, in the MDC, according to the classification made by the authors in the publications, which was sometimes not appropriate. Until the unique criteria are defined, the classification problem will persist.

Hence, also in view of the reasons mentioned in Section 3 for which the average orbits of the same stream may differ, we decided to continue this study. Our approach allows us to eliminate clearly incorrect solutions in the MDC, and contributes to the understanding of how to ascertain whether a new solution could be a duplicate of an existing meteoroid stream, crucial for the discovery of new meteor showers.

During the research described in Paper I we limited ourselves to the streams available at MDC until December 2022, with complete orbital data. Currently, we are discussing in detail the individual cases identified in Paper I as false duplicates. To this end, we also included in our considerations those data that arrived at the MDC database after December 2022, as well as those available in the literature but never entered into the database.

Fig. 1 Positions of radiants (depicted by red asterisks) of the three solutions of 11/EVI shower. The star η-Virginis is shown with a cyan circle, and the positions of the other stars are shown with black circles.

4.1 MSSs with three or four members

11/EVI, eta-Virginids. For the three solutions of this MSS, we have DH_Min=0.322 and DH_MI=0.079, strongly suggesting erroneous values for some of the stream parameters or incorrect classification. The four meteors of the first solution 11/EVI/00 were identified by Lindblad (1971a) among the 2400 orbits of meteoroids photographed in the 1950s. In Table 1a and 1b of Lindblad (1971a), the shower is called Northern Virginids. The parameters of the second solution 11/EVI/01, according to Jenniskens (2006) (p. 699, Table 7), were calculated by averaging 7 meteoroids. However, we have not been able to determine when and by which technique these 7 objects were observed, or the size sample in which this stream was identified. The third solution 11/EVI/06 was recently given by Shiba (2022), who sampled 298 689 orbits of automatic TV meteor observation network (“SonotaCo consortium”) and identified 158 members of this shower. In Table B.1, the averaged orbital elements of this MSS differ significantly in q, and the spatial orientation of the orbit, see Table C.1. However, for the second solution the internal consistency test failed. Similarly to Koseki (2016) (see Table 7 in his paper) we were not able to recalculate the orbital elements using the corresponding geocentric parameters of this shower. Therefore, we recommend moving solution 11/EVI/01 to the list of removed showers’ data.

The geocentric and heliocentric parameters of the other two solutions of this stream are internally consistent. However, the similarity of their orbits is highly questionable at DH_Min = 0.326, which is significantly too high to support the hypothesis that these two solutions involve the same stream. In the domain of geocentric parameters, these two solutions have clearly different values of geocentric velocity, 36.0 km s⁻¹ and 27.3 km s⁻¹, respectively. In addition, their radiants fall into two different constellations Leo and Virgo, see Figure 1. Due to these reasons, solution 11/EVI/00 should be considered a false duplicate of the eta-Virginids shower. Hence, in the MDC database, this shower should be represented by a single solution 11/EVI/06. We propose that solution 11/EVI/00 be moved to the MDC Working list, as a stand-alone shower with the original name Northern Virginids as proposed in Lindblad (1971a), and be assigned new IAU MDC codes.

The current status of the shower 11/EVI is established. However, after the reclassification of its two incorrect solutions, it no longer fulfils the criteria for this status. If the IAU MDC does not receive a new submission for the shower, it should be considered for reassignment to the Working list. All procedures for changing the status of a shower, or for reclassifying solutions or changing their names, must be approved by the IAU Working Group on Meteor Shower Nomenclature (WG)⁴.

107/DCH, delta-Chamaeleontids. The stream is represented by three solutions; DH_min = 0.358 and DH_MI = 0.136 differ significantly. The geocentric and heliocentric parameters of these solutions are internally compatible. Solutions 107/00 and 107/01 are taken from Gartrell & Elford (1975), where, in Table 1, the authors assigned them two distinct designations 2.15 and 2.14, respectively. Their classification as a single shower and the name of the shower, delta-Chamaeleontids, were later proposed by Jenniskens (2006). Jopek et al. (1999) partly confirmed the identification of solution 107/01, using a different approach and more numerous orbital sample than Gartrell and Elford. In his paper, Jopek gave the stream the name Chamaeleontids. In the MDC database, this solution is designated as 107/DCH/02. All solutions of this MSS come from the radar meteor data sample, Gartrell and Elford searched 1667 orbits, Jopek used the same orbits and additionally included 2101 ones. All orbits were determined by the Adelaide radio meteor system in Australia. Solution 107/00 was obtained from only 4 orbits, the others, 107/01 and 107/02, from 47 and 33 orbits, respectively.

The geocentric parameters and orbits of these solutions differ markedly. In particular, the values of the geocentric velocity, eccentricity, and inclination of the orbits. The positions of their radiants differ significantly, as can be seen in Figure 2. The radiant 107/00 lies in the constellation Octans, far from the constellation Chamaeleon. The other radiants are located on the outskirts of the constellations Chamaeleon and Apus (radiant 107/01), and Chamaeleon and Octans (radiant 107/02). The arithmetic mean value of the orbital similarity taken from all pairs of this MSS <DH>=0.388. However, the orbital similarity of solutions 107/00 and 107/01 is DH = 0.526 and for solutions 107/00 and 107/02 we have DH = 0.358. For solutions 107/01 and 107/02, the orbital similarity takes the value DH = 0.279, see Table C.1. For this reason, we can agree with Gartrell & Elford (1975), who in their study, concluded that solutions 107/00 and 107/01 represent two different streams. Hence, we recommend that solution 107/00 be a stand-alone shower. Without the 107/00 solution, the similarity of the other two solutions as measured by the DH-function has improved and is DH_Min = 0.279, though it remains significantly higher than the maximum DH_MI = 0.059 threshold allowed for this pair. It should be noted that solutions 107/01 and 107/02 were obtained from two partly overlapping orbital samples, so they cannot be considered fully independent solutions.

We suggest a further study of this MSS, in which the variability of the orbits of the members of this group will be recognised by means of computer simulation. Perhaps we are dealing with a case of a toroidal stream whose orbits undergo rapid dispersion, which would explain the high value of DH = 0.526 determined for solutions 107/01 and 107/02 of this stream. Until then, all three solutions should represent three showers on the MDC Working list, with 107/00 and 107/02 receiving new names and codes approved by the WG, while 107/01 retains the current shower name, delta-Chamaeleontids (see Figure 2).

121/NHY nu-Hydrids. For the three members of this MSS, DH_Min = 0.269 and DH_MI = 0.079 differ significantly. As noted in Koseki (2016), there is an internal inconsistency in the geohelio data of solution 121/NHY/00 given by Terentjeva (1989). According to Koseki, the reason for the discrepancy is a typographical error in the value of RA = 158° in Terentjeva (1989). In order to remove the data inconsistency of this solution, Koseki proposes RA = 168.6°. An analogous conclusion follows from our calculations, but since for right ascension Terentjeva (1989) gives only three significant digits in her paper, the correction of the typographical error should be RA = 168° in the B1950 reference frame.

When it comes to the name of this shower, we are facing another problem. The parameters of the 121/NHY/02 solution are taken from Sekanina (1976), where the author named the identified meteoroid stream, rho-Leonids (Table VI, p. 275) according to its radiant position in the constellation Leo near the star ρ Leonis, see Figure 3. In Gartrell & Elford (1975), the solution 121/NHY/03 is not named; instead, the authors proposed the code 3.02, only. Terentjeva (1989) proposed the name nu-Hydrids for the solution 121/NHY/00, but she most likely did so based on the coordinate RA = 158° for this shower, which has now been found to be erroneous, causing an internal inconsistency in the data she gave for this shower. The corrected radiant, with a value of RA = 168° (B1950), lies in the constellation Crater near the star δ Crateris, see Figure 3. Consequently, none of the three shower solutions 121/NHY, has a radiant located in the constellation Hydra. Each is located in a different constellation: Crater, Leo and Sextans.

Returning to the similarity assessment of the orbits, a comparison of all pairs of orbits for 121/NHY showed that their DH values range from 0.201 to 0.289, see Table C.1. They are too different from the threshold value of D_MI = 0.059 allowed for these pairs, but, on the other hand, they do not differ enough to determine which of the 121/NHY solutions can be considered a false duplicate. Rather, it would be more appropriate to state that none of the solutions given in Table B.1 are members of the 121/NHY shower, but that they are three autonomous showers. Our recommendation is to keep these solutions on the MDC Working list as stand-alone streams. We propose that solution 121/NHY/02 retain, if possible, a variation of its original name as given in Sekanina (1976), e.g. Southern rho-Leonids, while the other two solutions be assigned new names and codes. Shower 121/NHY will be simultaneously moved to the MDC List of removed showers to ensure the traceability and identification of all solutions. Alternatively, to minimize changes, one of the solutions could retain the current shower name despite the inconsistency with the old nomenclature rules; the decision will be made by the WG.

152/NOC Northern Daytime omega-Cetids. For this shower, the value of DH_Min = 0.644 is significantly higher than the orbital similarity threshold of DH_MI = 0.182, acceptable to a group of four members. The first three solutions were identified among radio meteors, the fourth among video-observed meteors. Solution 152/NOC/00 was determined by Sekanina (1976), who named it gamma-Pegasids. Solution 152/NOC/01 was by Nilsson (1964b), who in Table 4 of his paper designated it as “Gr. 61.5.3.” This shower consists of ten members. Nilsson’s identification turned out to be correct, as it was confirmed by a completely different cluster analysis method by Jopek et al. (1999). In Table 1 of that work, the stream is named alpha-Arietids. Solutions 152/NOC/02 and 152/NOC/04 were identified by Brown et al. (2008) and Shiba (2022), respectively. The radiants of all four solutions are located in three constellations: Aries, Pisces and Pegasus, see Figure 4. It is not specified in Jenniskens (2006) why the shower was given a name related to the constellation Cetus.

In Table B.1 and Table 1, compared to the others, the second solution, 152/NOC/01 has different values of orbital angular elements. In particular, it has a much smaller orbit inclination value i = 10.2°. The cluster analysis performed without 152/NOC/01 solution showed that the three remaining solutions can be identified as MSS with DH_Min = 0.193 which is close to the acceptable value of DH_MI = 0.136 for three members of the shower. As a result of this analysis we can consider the second solution given in Table B.1 as a false duplicate of the 152/NOC stream. We therefore recommend that 152/NOC/01 be reclassified in the MDC database as a stand-alone shower with a new name and IAU MDC codes assigned.

However, one issue remains, for two solutions, 152/NOC/02 and 152/NOC/04, we found an internal inconsistency in the data. The data for these streams comes from the source works by Brown et al. (2008) and Shiba (2022), respectively. However, in both cases the inconsistency of the data is close to the assumed critical values of the differences between the parameters calculated by us and those given in the MDC database, (see Section 3). Which, in our opinion, justifies leaving these solutions as duplicates of the 152/NOC meteor shower. This shower has already passed the status of an established shower and the elimination of solution 152/NOC/01, based on ten orbits, will not affect this status.

183/PAU Piscis Austrinids. For the three solutions to this shower, DH_Min = 0.294 while, the acceptable threshold value, DH_MI = 0.136. The first two solutions were obtained from radio observations and the third with video cameras. The 183/PAU/00 solution is from Kashcheyev & Lebedinets (1967), the 183/PAU/01 was given by Brown et al. (2008), the third 183/PAU/04 was given by Jenniskens et al. (2016a). The geo-helio data of these solutions are internally consistent, but the values of the parameters of the first one are clearly different from the others, especially the values of the inclination of the orbits and the geocentric velocities, see Table B.1.

When one ignores the orbit of 183/00, the orbital similarity of the other two solutions is DH_Min = 0.241, see Table C.1, which for the remaining pair of solutions still far exceeds the allowable value of DH_MI = 0.056. However, in the MDC database there is another solution of this shower provided by Shiba (2023), that was not used in Paper I, because the shower data have been submitted to the MDC after December 2022, the date to which we were limited in selecting the research sample in Paper I. Taking into account the solution 183/06 in MDC and at the same time removing 183/0, for these three solutions, we obtained DH_MI = 0.191 with a cut-off value of DH_MI = 0.146. And given the comments mentioned in Section 3, these solutions can be considered to represent the same meteoroid stream, especially since we are dealing here with the different way each author averaged the elements of the orbits. Brown calculated the elements of the orbits based on averaged values of geocentric parameters; Jenniskens gave medians; and Shiba counted the arithmetic means of the elements of the stream members’ orbits.

In view of the above, despite the fact that only the radiant of solution 183/00 is located in the constellation Piscis Austrinus, the others are in the constellation Aquarius, see Figure 5, we propose that solutions 183/01, 183/04 remain unchanged in the MDC. On the other hand, we propose that stream 183/00 be given autonomous status with a new name and codes. The shower 183/PAU remains established since removing one of the four current solutions does not affect its status.

188/XRI Daytime xi-Orionids. The values DH_Min = 0.534 and D_MI = 0.079 clearly show that there is a misclassification among the solutions of this MSS. All solutions were obtained from radio observations. Nilsson (1964b) did not provide the name of the identified stream, among 2101 orbits he identified only 3 members of his stream. Similarly for 188/XRI/01, the name of the shower is not provided in Kashcheyev & Lebedinets (1967); the name of the Daytime xi-Orionids is given in Brown et al. (2008). The positions of the radiants for these solutions are shown in Figure 6. Only the radiant given by Nilsson lies in the constellation Orion, the other two lie in the constellation Gemini.

In Tables B.1 and C.1, we see that the parameters of the 188/XRI/01 solution differ from the others. This solution was recently suggested to correspond to another SSS shower, 1211/SFG, from the Working list (Jenniskens 2023), though this association was not confirmed by the methods we used. Excluding solution 188/01 makes DH_Min = 0.268 and DH_MI = 0.036, which still means that we are not dealing with duplicates here. In the absence of access to the source data that the authors of these solutions used to calculate the averaged parameter values, further consideration cannot take place. However, within the framework of the methodology used, all 188/XRI solutions should be treated as stand-alone showers. Since 188/XRI is on the List of established showers, we propose to change its status and move all three solutions back to the Working list. Solution 188/00 will retain the codes and name Daytime xi-Orionids, while 188/01 and 188/02 will be assigned new names and codes.

219/SAR September mu-Arietids. The shower is represented by four solutions, all obtained from observations of radio meteors; one solution (219/SAR/00) comes from the work of Nilsson (1964b), the other three were given by Sekanina (1976). As we read in the original papers, Nilsson (in Table 4) named his shower as Gr.61.9.3; Sekanina considered the three solutions (219/01, 219/02 and 219/03) to be separate streams and named them (in Table 6) gamma-Arietids, rho-Piscis-Arietids and Arietids-Piscids, respectively. In Figure 7, Nilsson’s 219/SAR/00 solution has a radiant located deep within the constellation Pisces near the star 87-Piscium. Sekanina’s 219/SAR/01 solution with a radiant near the star γ-Arietis has a name in line with the old rules for naming meteoroid streams (Jopek et al. 2023). The 219/SAR/02 solution has a radiant near the star 97-Piscium, roughly in the middle, between the stars ρ-Piscium and γ-Arietis. The third solution given by Sekanina, 219/SAR/03 has a radiant in the constellation Aries, but the closest star to this radiant is π-Piscium. Neither of these corresponds to the name September mu-Arietids given for these solutions in Jenniskens (2006).

For this group, we have DH_Min = 0.373 and DH_MI = 0.099, suggesting that we are dealing here with an inappropriate classification of duplicates. The DH-values of all pairs of orbits of 219/SAR range from 0.217 to 0.580, see Table C.1. Faced with an acceptable threshold value of DH_MI = 0.059 for pairs in the studied set of orbits, this means that, according to the methodology used in this work, it is impossible to identify these four solutions as duplicates of the same meteoroid stream. We therefore recommend that they be assigned the status of autonomous streams on the MDC Working list, with names given by their discoverers or new names together with stream codes set by the WG. Simultaneously, shower 219/SAR with a name September mu-Arietids will be moved to the List of removed showers.

Fig. 2 Positions of radiants (depicted by red asterisks) of three solutions of shower delta-Chamaeleontids, 107/DCH. The position of double star δ-Chamaeleontis is shown with a cyan circle; the positions of the other stars are shown with black circles.

Fig. 3 Positions of the radiants of three solutions of shower 121/NHY nu-Hydrids (red asterisks). The originally published erroneous position of the solution 121/0 is shown with the orange asterisk. The purple line shows the ecliptic. Stars v-Hydrae, ρ-Leonis, and δ-Crateris are plotted with the cyan circles. The other stars are shown with black circles.

Fig. 4 Positions of the radiants of four solutions of shower 152/NOC Northern Daytime omega-Cetids (red asterisks). One can see that no solution is located in the constellation Cetus, however. The stars are depicted with black circles. The purple curve indicates the ecliptic.

Fig. 5 Positions of the radiants of three solutions of shower 183/PAU Piscis Austrinids (red asterisks). Only the solution 183/PAU/00 is located in the constellation Piscis Austrinus. Two other solutions, 183/PAU/01 and 183/PAU/04, are located in the constellation Aquarius. The stars are depicted with black circles.

Fig. 6 Positions of the radiants of three solutions of shower 188/XRI xi-Orionids (red asterisks). Stars ξ-Orionis and γ-Geminorum are plotted with the cyan circles; the other stars are shown with black circles.

Fig. 7 Positions of four soof the radiants lutions of shower 219/SAR September mu-Arietids (red asterisks). Stars μ-Arietis, γ-Arietis, ρ-Piscium, 97-Piscium, 87-Piscium, and π-Piscium are shown with cyan circles. The other stars are depicted with black circles. The purple curve indicates the ecliptic.

4.2 MSSs with two members

In this subsection, we discuss the MSSs given in the third section of Table 1 for which we have only two solutions in our data sample. The threshold values of the DH functions involved here (DH_MI = 0.039 for orbits with i ≤ 10°, DH_MI = 0.059 for i > 10°) do not depend on the cluster analysis method used. Therefore, as mentioned above, based on the DH_P values from Table C.1, and the DH_MI values of Table 1, it can be categorically stated that we have a misclassification among these MSSs.

However, using only DH_MI and DH_P, we cannot conclude which of these solutions is a false duplicate. Therefore, in order to identify a solution that may be a false duplicate, we used additional information, such as: the inconsistency between geocentric and heliocentric shower data, the number of meteoroids identified in a given solution, and the difference in observation epochs of members of a given solution. We also took into account the averaged position of the shower radiants and the fact of a solution’s association with a potentially parent comet.

25/NOA Northern October delta-Arietids. The DH_Min = 0.210 and DH_MI = 0.039. The solutions 25/00 and 25/01 differ significantly in V_g, (~6 km s⁻¹) and in the inclination of the orbits (~7°). The two solutions are separated by ~40 years in observation epochs, which may account for the sizeable value DH_Min.

For the 25/01 solution, using the two cluster analysis methods used in Paper I (single linking method and maximum sigma method), it was found to belong to a complex structure of 62 solutions, involving more than a dozen streams, among which the Northern and Southern Taurids dominate (17/NTA, 2/STA). So, because the 25/01 radiant has positive ecliptic latitude, we propose that this solution be included in 17/NTA. An analogous suggestion is given in Jenniskens (2006, 2023).

In Paper I, we did not find that 25/00 belongs to any of the streams collected in the MDC database; therefore, we propose that this solution be classified as an autonomous stream in the MDC. In the original article by Kashcheyev & Lebedinets (1967) in Tab 4.8, this shower was designated as No.161. Hence, we propose that the 25/00 solution remain in MDC while retaining the current codes and name.

32/DLM December Leonis Minorids. Both solutions found internal data inconsistencies at the limit of our acceptable tolerance. Based on the values of DH_Min = 0.321 and DH_MI = 0.059, both 32/DLM solutions should be considered autonomous. However, after inspecting the entire MDC catalogue of stream data, it turned out that the 20/COM/06 and 32/DLM/01 solutions are exactly the same. This error was recognized earlier by Koseki (2020). So, after correcting this mistake, the problem of misclassification of stream 32/DLM was solved. The erroneous solution 32/01 with the appropriate annotation will be moved to the List of removed showers.

40/ZCY zeta-Cygnids. For this MSS, we have DH_Min = 0.259 and DH_MI = 0.059. The time interval separating the observation epochs of the two solutions is about 40 years. 30 members of the 40/00 solution among nearly 20 000 radio observations identified by Sekanina (1976); 64 members of the 40/02 solution among ~110 000 video orbits identified by Jenniskens et al. (2016a). The e and q parameters of the orbits of both solutions are very similar, but they differ significantly in the inclination of the orbits, by ~8°, making DH_in = 0.250 in Table C.1. Also for this pair Koseki (2020) noticed the large difference in mean solar longitude, Δλ_S = ~13°.

We are unable to determine the reason for such a large difference in the inclination of the orbits. Hence, we propose that solution 40/00 named April Cygnids by its discoverer (Sekanina (1976), Tab. VI, p. 276) be given autonomous status, and solution 40/02 be left unchanged in the MDC. However, we have a second option for this MSS. Taking into account the 40/04 solution recently provided by Shiba, we obtained DH_Min = 0.175, which, together with the D_MI = 0.136 value for the three orbits, allows us to leave all 40/ZCY solutions in the MDC database without making changes.

76/KAQ kappa-Aquariids. The corresponding DH values are DH_Min = 0.142 and DH_MI = 0.039. Both solutions, 76/KAQ/00 and 76/KAQ/01 were identified among the photographic orbits by Porubčan & Gavajdová (1994) and Lindblad (1971b), respectively. The numbers of identified members are very small 3 and 4; and the identifications were not made in independent samples of orbits – there was some overlap between the samples of orbits tested in Porubčan & Gavajdová (1994) and Lindblad (1971b). The main orbital difference between the solutions 76/KAQ/00 and 76/KAQ/01 is due to the orientation of the orbits’ apse lines. In Table C.1, the value DH_Π = 0.121, clearly brings the largest contribution to DH_Min = 0.142. Koseki (2020) points out the large mutual angular distance of the radiants of the two solutions. In particular, he stated that the solutions are indistinguishable from the sporadic background.

As can be seen in Table B.1, the parameters of the 76/KAQ/01 solution are not internally consistent. The reason for this is the value of the geocentric velocity of the meteoroid given in the original article Lindblad (1971b) as V_g = 19 km s⁻¹. Lindblad also lists the catalogue numbers of the meteoroids included in this stream. Taking advantage of this special circumstance, we recalculated the arithmetic mean of the geocentric velocity of this solution, which yielded the value V_g = 14.23 km s⁻¹. And its application removed the inconsistency in the parameters of the 76/KAQ/01 stream. However, the corrected V_g mean value does not affect the poor similarity of the orbits of the 76/KAQ/00 and 76/KAQ/01 solutions.

Moreover, as stated in Neslušan et al. (2023) and as can also be seen in Table B.1, both solutions involve two branches of the 76/KAQ stream – the ecliptic latitudes of their radiants differ in sign, see Figure 8. This means that their status in the MDC will have to be changed. In Lindblad (1971b) and Porubčan & Gavajdová (1994) these streams were named kappa-Aquariids and September iota-Aquariids, respectively. We propose splitting the two solutions in the MDC and, in accordance with the suggestion by Neslušan et al. (2023), renaming solution 76/00 to September iota-Aquariids, as originally proposed by Porubčan and Gavajdová and assigning it a new numerical and letter code. The solution 76/01 would retain the current shower name kappa-Aquariids and codes 76/KAQ.

88/ODR omicron-Draconids. The DH_Min = 0.362 and DH_MI = 0.059 clearly indicate the misclassification of one of the solutions. 14 members of 88/ODR/00 were identified among radio meteors by Sekanina (1976) and 63 members of 88/ODR/01 were identified among video data by Jenniskens et al. (2016a). The internal inconsistency of the 88/ODR/01 solution, see Table B.1, concerns the longitude of the ascending node of the orbit and is at the limit of the tolerance adopted in Neslušan et al. (2023). Probably it is due to the fact that Jenniskens et al. (2016a) reports medians as mean values of stream parameters. The geocentric velocities of the two 88/ODR solutions differ by about 10 km s⁻¹ which is the reason of the large components DH_e = 0.131, DH_in = 0.3 and DH_Π = 0.156, see Table C.1. Taking this into account, and because of the very large value of DH_Min = 0.362, we propose that both solutions be given the status of autonomous streams. Sekanina named his stream o-Draconids, and therefore we keep the old name/number/code of the shower and assign a new name/number/code only to the solution 88/01.

93/VEL Puppid-Velid II Complex. In Table 1 of Gartrell & Elford (1975) these streams were designed code 2.13 and 2.09, respectively, they were identified among 1667 radio meteoroid orbits. In Jenniskens (2006), they are considered components of Puppids-Velids II. In view of the decidedly large value of DH_Min = 0.412, for this MSS, which consists of contributions in both eccentricity, inclination and orientation of the lines of the apses, DH_e = 0.33, DH_in = 0.213, DH_Π = 0.118, respectively, the 93/VEL/00 and 93/VEL/01 solutions should be stand-alone streams in the MDC. There are also large differences in the geocentric parameters of these solutions. The meteors of these showers were observed in the same month of the same year, and yet the difference in the ecliptic longitudes of their radiants in the rotating reference system is nearly 40 degrees! Undoubtedly, this has some relation to the large difference in the position of the radiants of the two solutions, Koseki (2020) noted that the radiants differ by 19 degrees in the right ascension and by 15 degrees in the declination; see Figure 9. Hence, we believe that the 93/00 and 93/01 solutions should be stand-alone streams in the MDC. Specifically, solution 93/VEL/01 with the radiant in the constellation Vela, near the border with the constellation Puppis, should remain unchanged in the MDC, except for omitting the Roman enumeration II and word ‘Complex’ in its name (it is a shower, not a complex) and solution 93/VEL/00 should obtain a new IAU No., code, and name; its radiant is situated in constellation Carina.

100/XSA Daytime xi-Sagittariids. The values of DH_Min = 0.209 and DH_MI = 0.039 point to the misclassification of solutions of this MSS. Both solutions, 100/00 and 100/01, Sekanina (1976) identified among ~20 000 orbits of meteoroids observed from December 1968 to December 1969 (so-called synotpic-year sample). In Sekanina’s work, these solutions are separate streams, their discoverer gave them the names January Sagittariids and xi-Sagittariids (Table VI, p. 274), respectively. Their fusion as representatives of a single shower was introduced in Jenniskens (2006). The mean orbits of these solutions differ mainly in q and Π (see Table C.1), the respective values of DH_q = 0.147 and DH_Π = 0.131 clearly exceed the acceptable threshold of orbital similarity DH_MI = 0.039 for orbits with low inclination. Thus, we suggest that the two solutions be treated as stand-alone showers on the MDC Working list, with solution 100/01 retaining its current IAU MDC designation. For solution 100/00, we suggest assigning a new code and restoring the name as proposed by the discoverer. At the same time, we propose moving 100/XSA to the MDC Working list. Introducing an established status to this shower has clearly failed. As in all cases, the final decision will be made by the Working Group on Meteor Shower Nomenclature.

105/OCN Centaurid I Complex. Both solutions were identified in radio orbit samples, Gartrell & Elford (1975) searched 1667 orbits, Nilsson (1964a) 2101 orbits. Gartrell & Elford (1975) named their stream as Carinids. How Nilsson labelled his solution we could not determine. In Kronk (1988), the stream was called eta-Carinids. However, in view of the small number of members of these solutions (3 members each), their reality is supported by the fact that they were discovered in two observation campaigns. The first in January 1961 and the second in January 1969. It is worth mentioning that the 150/00 solution was obtained from meteor observations observed from January 21–23, 1969. In January, outside this interval, the radar equipment was not working. This means that the meteoroids observed over the three days will have similar values for the longitude of ascending nodes. Thus, here we have a reduction, from four to three dimensions, of the issue of similarity of the determined orbits.

The flag visible in the first column of Table B.1 indicating that the data of the 105/OCN/01 solution are inconsistent is due to the erroneously reported λ_s = 323.4° in the IAU MDC. In view of the large value of the orbit inclination of this stream, this value should be λ_s = 299.7°, which is almost equal to the value of the longitude of the ascending node of the orbit, increased by 180°. The erroneous value of λ_S does not enter into the calculated DH value. For the pair 105/00 and 105/01, it is DH_Min = 0.134, which, in view of the threshold value of DH_MI = 0.059, may indicate that these solutions are unjustifiably considered to represent the same meteoroid stream.

The abundance of both solutions, N=3, is therefore very low which, in the absence of other orbital data of this shower in MDC, may indicate its spurious nature. Admittedly (in a sample of orbits that is a combination of those used by Nilsson and Gartrell, Elford), Jopek et al. (1999) identified 6 Carinids with similar parameters to the solutions given by Nilsson and Gartrell and Elford. However, the solution obtained by Jopek et al. (1999) cannot be considered an independent confirmation of solutions 105/00 and 105/01. Hence, in view of the above, and due to the quite large value of DH_Min=0.134 for this MSS, we believe that we have a clear basis for considering both its solutions as autonomous.

We believe the best course of action in this case is to move the 105/OCN Centaurid I Complex to the List of Removed Showers while keeping solution 105/00 on the Working List with a new IAU MDC code and a new name based on its radiant position. The radiant is located near the same star, theta Carinae; see Figure 10. At the same time, both solutions, under the current shower name and code, will be moved to the List of removed showers.

106/API alpha-Pictorids. The values of DH_Min = 0.329 and DH_MI = 0.059 indicate the misclassification of these solutions as belonging to the same shower. The dominant contributors to such a high DH_Min value are the differences in the eccentricity and orientation of the two orbits, DH_e = 0.22 and DH_Π = 0.244, respectively (Koseki (2020) stated an angular distance of radiant larger than 10°; see Fig. 11. Such differences cannot be justified by the daytime motion of the radiant because meteors of both solutions were observed within a few days during February of the same year (i.e. 1969). The streams were identified by Gartrell & Elford (1975) radio sample of 1667 orbits. Streams 106/API/00 and 106/API/01 included a small number of 3 and 5 members, respectively. In Table 1 of Gartrell and Elford’s publication, the authors only proposed designations for their findings, namely 2.10 and 2.11.

Regardless of the questionable nature of the 106/API solutions, we propose that they remain on the MDC working list as stand-alone solutions. For both solutions, we propose new IAU MDC codes and names in accordance with the old nomenclature rules (see Fig. 11). Alternatively, one of them could retain its current designation. The WG will finalize the decision.

108/BTU beta-Tucanids. The values of DH_Min = 0.344 and DH_MI = 0.059 indicate the misclassification of at least one of the solutions 108/00 or 108/01. Their discoverers, Gartrell & Elford (1975), proposed 3.05 and 3.04 as designations for their findings. Ten and eleven members of these streams were identified among 1667 radio orbits. Both solutions have similar orbits, except for the eccentricities, in Table C.1 we have DH_e = 0.34, the other contributions have irrelevant influence. Apart from the two solutions mentioned, no information has been provided to the IAU MDC on further identification of this stream. However, in the literature, an outburst observed by the SAAMER radar in 2020 was claimed by Bruzzone et al. (2021) to match two showers, 108/BTU and 130/DME. In 2021, Jenniskens (2021) reported the detection of 29 meteors belonging to 108/BTU. Koseki (2020) also found an association of 108/BTU and 130/DME. However, shower 130/DME, the delta-Mensids, was moved to the list of removed showers because of the lack of complete data.

Despite the similarity of some parameters, the two solutions of this MSS in the face of a significant difference, Δ V_g = 4.2 km s⁻¹, in geocentric velocity and eccentricity value, Δe = 0.34, should be considered autonomous. We propose, due to its use in the literature, keeping the codes 108/BTU and name beta-Tucanids for one of the solutions, despite the fact that it was not assigned to the shower in accordance with the nomenclature rules. The other solution will be given new codes and name corresponding to its radiant, see Figure 12. The decision will require thorough discussion within the WG.

113/SDL Southern delta-Leonids. The values of DH_Min=0.172 and DH_MI = 0.039 indicate the misclassification of at least one of the solutions. Solution 113/SDL/00 was named, in the source publication by Terentjeva (1989) as α-Cnc (c), alpha-Cancrids. According to the test we performed, the parameters of this solution are not internally consistent, which was also found by Koseki (2016). Koseki suggests that the declination value of the radiant given by Terentjeva is incorrect and should be δ = 7.8°. With such a declination value of the radiant, its ecliptic latitude would have a negative value, which would remove the second problem of having together northern and southern branches in a single shower. The radiants of both solutions 113/SDL/00 and 113/SDL/01 would then belong to the southern branch of this stream. However, such a correction does not change the orbital similarity of the two solutions. Their orbits differ mainly in the distance of the perihelion and the orientation of the apses line, DH_q = 0.114, DH_Π = 0.122. Solution 113/SDL/01 (Sekanina 1976) was identified among 1968–1969 synoptic-year sample of ~20 000 radio meteors. Terentjeva (1989) identified her solution among 554 fireballs observed by the US and Canada fireball networks during 1963–1984.

In view of the significant value of DH_Min = 0.172, we believe that both streams should be treated as autonomous in the IAU MDC. Since the original name from Terentjeva’s work, is already in use by another stream, 266/ACC/00, alpha-Cancrids, identified by Porubčan & Gavajdová (1994), we propose that this solution be named pi1-Cancrids (see Figure 13), with new codes assigned. Since none of the two solutions has a radiant consistent with the shower designation, for the solution given by Sekanina, we suggest assigning a new IAU MDC designation.

118/GNO gamma-Normids. The extremely large value of DH_Min = 0.798 in comparison to DH_MI = 0.059 unquestionably indicates the misclassification of at least one of the solutions for this stream. Both analysed solutions were identified by Gartrell & Elford (1975), determined among a sample of 1667 radio meteors observed from December 1968 to October 1969. The numbers of members of these solutions are low, 118/00/GNO was obtained from averaging 3 orbits, 118/01/GNO from 6 orbits. In the second solution, we found inconsistency among the geohelio data, albeit at the borderline of the applied maximum-error tolerance. In Table 1 of the paper Gartrell & Elford (1975), the authors designate these streams with the codes ‘3.14’ and ‘3.15’, and later by Jenniskens (2006) these solutions were proposed as duplicates of the 118/GNO stream.

In the MDC database, we obtained two other submissions for this stream, provided by Jenniskens (1994) and Molau & Kerr (2014); however, the full set of orbital elements is not given by the authors. Therefore, the similarity of their orbits cannot be verified. Moreover, as stated in Durišová et al. (2024), on the inc versus 1 / Q plane (inclination of the orbit versus the inverse of the aphelion distance), the points representing this stream are in an area where there are no currently known comets or NEAs. These facts support the claim that both solutions 118/00 and 118/01 could have been identified as meteoroid streams by chance only. The solutions of 118/GNO were regarded as an unreasonable combination of orbits by Koseki (2020). Thus, the most appropriate recommendation would be to exclude solutions 118/00 and 118/01 from the Working list of showers, and place them on the List of removed showers’ data.

124/SVI Southern March Virginids. The DH_Min = 0.226 and DH_MI = 0.039 values for this stream indicate the misclassification of at least one of the solutions. Both solutions were identified among the radio orbits of meteors observed during 1961/65, solution 124/SVI/00, and during 1959/60, solution 124/SVI/01. The first one identified by Sekanina (1973) includes 13 members and the second one identified by Kashcheyev & Lebedinets (1967) includes only 5 members. Their orbits differ mainly in the inclination and orientation of the apses line: DH_in = 0.105 and DH_Π = 0.177 respectively, see Table C.1.

We suggest that these solutions should not be considered as representations of the same stream. The stream he discovered, Sekanina called Southern eta-Virginids, so we would prefer to keep the current name “Southern March Virginids” and codes for this solution: 124/SVI/00. Solution 124/01 has a radiant located in the constellation of Leo, near the star ϵ Leonis, see Figure 14. In Kashcheyev & Lebedinets (1967), this stream was named δ Leonids. Therefore, after moving the ‘old’ 124/SVI/01 solution to the List of removed showers, we propose to leave it in the MDC with the original name but with the codes established by the WG.

128/MKA Daytime kappa-Aquariids. The values of DH_Min = 0.315 and DH_MI = 0.039 for this stream indicate that the misclassification also occurred in this case. Both solutions were identified among radio meteors observed with radar at the Adelaide station. Gartrell & Elford (1975) among 1667 orbits identified 7 meteoroids, solution 128/MKA/00. Nilsson (1964b) among 2101 orbits identified only 3 members of the 128/MKA/01 stream. The parameters reported by Nilsson are internally inconsistent but at the limit of our accepted error tolerance. The orbits of the 128/MKA differ significantly in the perihelion distance and the orientation of the apses line, DH_q = 0.25, DH_Π = 0.189. Jopek et al. (1999), in a total sample of 1667+2101 orbits, identified an alpha-Aquariids stream of 16 orbits that appears likely to contain members of the 128/MKA/00 and 128/MKA/01 solutions. In the MDC database, the values of the mean perihelia distances of the streams identified by Nilsson were necessarily calculated using values of the eccentricities and inverses of the semi-major axes. Using the uncertainties of these quantities given by Nilsson, in the case of shower 128/MKA/01, the perihelion distance could just as well have been q = 0.2653 au, instead of the q = 0.3 au used in our calculations. This, in turn, entails a decrease of DH_Min = 0.27 and DH_q = 0.191 for the 128/MKA. Unfortunately, we do not have the full information to proceed with this kind of calculation. We therefore have no way of confirming or rejecting the hypothesis that these solutions involve the same meteoroid stream.

For these reasons, and due to the close mutual positions of the radiant of the solutions 128/00 and 128/01 and that obtained by Jopek et al. (1999) (RA = 339°, DE = −7°) and by Brown et al. (2010) (RA = 332°, DE = −8.4°), we consider it appropriate to leave 128/00 / and 128/01 solutions in the MDC database without any changes.

133/PUM April psi-Ursae Majorids. The DH_Min = 0.139 and DH_MI = 0.039 values for this stream indicate the misclassification of one of the solutions. Following Jenniskens (2006), two solutions of the 133/PUM given in the MDC are 133/00 identified by Terentjeva (1989) among 554 bolide orbits, and 133/01 identified among ~20 000 radio meteors by Sekanina (1976). However, the discoverers of these streams, in their works, give other names to them: Terentjeva gave the name Lyn II (Lyncids II), Sekanina gave the name April Ursids. The mean orbits of these solutions differ mainly in the eccentricity and orientation of the apsidal lines: DH_e = 0.089, DH_Π = 0.096. However, these solutions differ significantly in the position of the meteor radiant, their right ascensions differing by about 30°. Also a large difference of λ_{RS C} = 20°, see Table B.1, occurs for the ecliptic longitudes of the radiants measured in the Sun-centred reference system. In this situation, the cause of these differences cannot be the diurnal motion of the radiant. Therefore, we consider that both solutions should be given autonomous status.

Based on Figure 15, we propose assigning a new name and codes for the stream discovered by Terentjeva, while keeping the name April psi-Ursae Majorids for the Sekanina stream, 133/PUM/01. To ensure that the 133/PUM/00 solution remains traceable it will be additionally listed in the List of removed showers under its old designation.

150/SOP Southern May Ophiuchids. The values of DH_Min = 0.343 and DH_MI = 0.039 for this stream clearly indicate the misclassification of one of the solutions. Both solutions were identified among meteors observed with video techniques. In Jopek et al. (2010a), among 231 orbits, 7 members of the 150/SOP/01 stream were found. They were observed in the New Zealand campaign in 2002 May. Shiba (2022) identified 115 members of the 150/SOP/08 solution among 298 687 meteors from the SonotaCo network observed during 2007–2020. As can be seen in Table C.1, the solutions differ markedly only in the orientation of the DH_Π = 0.329 apsidal line. This may indicate, unknown for us, a systematic factor differentiating these solutions. Therefore, we propose to give them the status of autonomous streams in the IAU MDC.

Since the radiant of the 150/SOP/01 solution is located in the constellation Ophiuchus (see Figure 16) and the members of the stream were observed within 10 days in May, we propose to keep the codes and name of this solution. The members of the 150/SOP/08 solution were observed in different years (from 2008 to 2020) at different times of the year (the ecliptic longitudes of the Sun differed by 30 days); hence, their observed radiants could take values from a relatively wide range. As can be seen in Figure 16, the mean radiant of this solution lies in the constellation Scorpius near the star pi-Scorpii. Due to its recent delivery to the MDC, we propose naming this solution in accordance with the new nomenclature rules (valid at the time of this submission), namely M2022-W1.

151/EAU epsilon-Aquilids. The values of DH_Min = 0.155 and DH_MI = 0.059 indicate a possible misclassification of the 151/00 or 151/01 solutions. 17 members of the first solution identified by Sekanina (1976) among ~20 000 radio meteors; 11 members of the 151/01 solution identified by Jenniskens et al. (2016a) in a sample of ~110 000 meteors observed with video cameras. We do not have any other solutions of this stream in the MDC, which may imply the lack of its annual activity and even, the random nature of their identification in samples of orbits determined at mutually distant epochs of osculation. As indicated in Table C.1, all contributors to DH_Min = 0.155 are of the same order, unlike, for example, for the 150/SOP stream, whose orbits differ mainly in the orientation of the apse lines. At this stage, we cannot show with certainty, but we are inclined to the opinion that similar causal values in the DH_Min value testify to the random nature of the difference in the parameters of the two 151/EAU stream solutions, which would support their autonomous nature. An additional argument for this conclusion is the nearly 10-degree difference in the right ascensions of the two radiants (see Figure 17) and the similar value of the difference in theλ_RCS – the ecliptic longitude of the radiant in the rotating reference frame. We propose that solution 151/EAU/00 remain unchanged, while solution 151/EAU/01 be given a new IAU name and codes. At the same time, we propose changing the status of 151/EAU and moving it from the List of established showers back to the Working list.

154/DEA Daytime epsilon-Arietids. The values of DH_Min = 0.178 and DH_MI = 0.039 indicate a possible misclassification of the 154/00 or 154/01 solutions. Both were identified among radio meteors, by Sekanina (1976) and Nilsson (1964a), respectively. Sekanina identified 25 members of the stream, Nilsson only 6 orbits. In Table C.1, we can see that, in principle, the solutions differ only in the orientation of the line of apsides, DH_Π = 0.177. Sekanina analysed ~20 000 orbits observed during the period 1968–1969, Nilsson 2101 orbits determined during the radio survey in 1961. Koseki (2020) pointed to a 15-degree difference in the Sun’s ecliptic longitude for these solutions. But in view of the almost identical values of λ_{RS C} (359.9° and 359.3°, see Table B.1), the differences in λ_S do not necessarily mean that we are dealing with different streams. Hence, we believe that both solutions involve the same stream, observed at different epochs.

167/NSS Northern sigma-Sagittariids. The values of DH_Min = 0.282 and DH_MI = 0.039 clearly indicate a misclassification of the 167/NSS solutions. Both solutions were identified in the same radio samples, by the same authors as in the previous case: Sekanina (1976) identified 45 members, Nilsson (1964b) only 4 members of 167/NSS stream. Sekanina gave his discovery the name sigma-Capricornids (which is inconsistent with old naming rules, see Figure 18), while Nilsson referred to it only as shower 61.6.6, see Table 4 of his paper. The reason for such a large value of DH_Min is the different orientation of the apse lines DH_Π = 0.256, see Table C.1. Other contributors to the DH_Min value are moderate, as is the case with the 154/DEA stream. However, the two solutions differ markedly in the radiants λ_{RS C} coordinate, the difference being ~8°. This difference cannot be explained by compensating for the perturbed motion of stream members over an interval of 8 years, equal to the difference in the epochs of observation of the two streams. In the absence of arguments in favour, we propose that these solutions be given the status of autonomous streams. We propose retaining the current shower name for the stream identified by Nilsson (167/01) and assigning a new IAU MDC designation to the Sekanina stream (167/00), see Figure 18.

170/JBO June Bootids. The values of DH_Min = 0.220 and DH_MI = 0.039 indicate a misclassification of the 170/JBO solutions. The 170/00 obtained by Sekanina (1976) among the ~20 000 radio orbits (54 members of the stream) has an internal inconsistency in the eccentricity. However, it can be considered acceptable within slightly expanded tolerance limits accepted in our calculations. In the second solution, 170/04 given by Shiba (2022), the 9 members identified among ~298 687 video orbits, differ from the first mainly in the orientation of the apse line, DH_Π = 0.203. The two solutions differ quite significantly in the equatorial coordinates of the radiant, ΔRA = 18°, ΔDec = 16°. These differences cannot be explained by the diurnal motion of the radiant, because the difference in the values of the ecliptic longitudes of the radiant in the rotating reference system, Δλ_{RS C} = 40°, is far too great. We therefore propose separating the two solutions.

As can be seen in Figure 19, the Shiba solution has a radiant inside the Bootes constellation, so we propose not to change its codes and name. For the solution 170/00, with a radiant close to the alpha-Draconis star, we propose restoring the name given to it by its discoverer, June alpha-Draconids (Sekanina 1976). This shower will be listed in the MDC as an autonomous shower, with new codes assigned. Since 170/JBO is on the list of established showers, its status must be reconsidered after excluding the 170/00 solution. The reconsideration will include three new solutions for 170/JBO recently submitted to the MDC by Roggemans et al. (2023).

179/SCA sigma-Capricornids. The values of DH_Min = 0.243 and DH_MI = 0.039 indicate a misclassification of the 179/SCA solutions. In the IAU MDC database, this stream is represented by 2 solutions: 179/00 identified by Sekanina (1976) among ~20 000 radio meteors and 179/01 identified by Jenniskens et al. (2016b) among ~110 000 video meteors observed after about 40 years. There is an inconsistency between the geocentric and heliocentric data for the 179/01 solution, most likely due to the way the averaged parameters were determined. In Jenniskens et al. (2016b) the authors took the medians of the parameters as average values.

The largest contributors to DH_Min = 0.234 are DH_e = 0.119 and DH_q = 0.172, which is undoubtedly due to the large difference in the geocentric velocities of the two solutions, Δ V_g = 7.2 km s⁻¹. The meteoroids of the solution 179/01 observed by the video technique by Jenniskens et al. (2016b) proved to be noticeably faster than those observed 40 years earlier by the radio technique of the solution 179/00. However, in his new publication, Jenniskens (2023) reports two solutions for this shower over different periods of activity, observing a decrease in velocity with decreasing λ_s. Unfortunately, the new solution has not been submitted to the MDC. Nor have we the data of the members of the 179/00 and 179/01 solutions at our disposal, which makes further discussion of this case difficult. In view of the significant value of DH_Min = 0.234, we favour giving both solutions the status of autonomous streams. For the first solution, 179/00, we suggest keeping the current designation of the shower, while for the solution 179/01, a new IAU designation should be assigned (see Figure 20).

186/EUM epsilon-Ursae Majoris. The values of DH_Min = 0.194 and DH_MI = 0.039 indicate that we are dealing with two different streams. Solution 186/00 was identified by Terentjeva (1989) among 554 photographic fireballs, solution 186/01 was found by Jenniskens et al. (2016b) among ~110 000 video orbits.

The solutions differ mainly in the inclination of the orbital planes DH_in = 0.109 and in the orientation of the apse lines DH_Π = 0.154. However, there is a distinctly large difference in the equatorial coordinates of the radiants, 41° in right ascension (see Figure 21), and in the rotating ecliptic reference system, Δ_{λRS C} = 63°. We do not have geocentric data as well as orbital data of the members of these solutions, which prevents further discussion of this case. Therefore, due to the large value of DH_min = 0.194, we propose to give autonomous status to both solutions.

The solution 186/00 given by Terentjeva (1989) could retain its current shower name and codes, while for solution 186/01, we propose a new name and new MDC codes assigned. Koseki (2020) pointed out a neighbourhood of 186/1 with shower 170/JBO. However, for 170/04 and 186/01, DH=0.079, the MSA test provided in Paper I failed.

189/DMC Daytime mu-Cancrids. The values of DH_Min = 0.454 and DH_MI = 0.039 indicate a misclassification of the 189/00 or 189/01 solution identified among the radio meteors observed in the 1960s by Sekanina (1976) and Nilsson (1964b), respectively. The orbits of the two solutions differ markedly in the orientation of the apse lines, DH_Π = 0.317, in the distance of the perihelia DH_q = 0.278 and in eccentricity DH_e = 0.158. The reason for such large values in the DH function is the different values of the geocentric velocities V_g = 24.3 km s⁻¹ and V_g = 33.1 km s⁻¹, and the different equatorial positions of the radiants not compensated for in the ecliptic rotating system Δλ_{RS C} = 8.5°. We propose that the two solutions be given the status of separate streams; stream 189/DMC/00 should be left on the Working list retaining the current shower name and codes, while solution 189/01 with radiant near the star 52-Geminorum, see Figure 22, should be left on this list with new codes and designation.

197/AUD August Draconids. The values of DH_Min = 0.316 and DH_MI = 0.039 indicate that we are dealing with two different streams. Sekanina (1976) identified solution 197/00 with 54 members among ~20 000 radio orbits, and Jenniskens et al. (2016a) found solution 197/01 with 17 members among ~110 000 video orbits. The main reason for such a large difference in DH value are eccentricities of the two orbits. Sekanina reported e = 0.335, Jenniskens et al. gave e = 0.644, which is probably due to the considerable difference in the geocentric velocity of the solutions, ΔV_g =~ 4 km s⁻¹. Another discrepancy between these solutions is the large difference in the ecliptic longitudes of the radiants, amounting to Δλ_{RS C} = 27°. The equatorial radiants of both solutions lie in the constellation Draco. We suggest to exclude the Sekanina solution from the 197/AUD. Unfortunately, the name phi-Draconids originally suggested by Sekanina has been used for another shower 45/PDF. Hence, we suggest giving it a new name and codes. As for the 197/01 solution, however, in order to keep the number of changes made to the MDC as small as possible, we propose that its name and codes be left unchanged in the MDC.

199/ADC August delta-Capricornids. The values of DH_Min = 0.107 and DH_MI = 0.039 indicate that we are dealing with two different streams. Regarding the previously discussed cases, the value of DH is not large, the main contributor comes from the DH_in = 0.08 related to difference in the inclination of the orbits of the two solutions. The smallest contribution comes from the orientation of the apse lines of the orbits, DH_Π = 0.006. Solution 199/ADC/00 was determined by Porubčan & Gavajdová (1994), and solution 199/ADC/02 was announced by Roggemans et al. (2022). However, the ecliptic latitudes of the two radiants have opposite signs. Which means that solutions 199/00 and 199/02 belong to separate branches of the same stream, and according to tradition, this property should be reflected in their names and codes. Therefore, we propose to rename solution 199/00 to Southern delta-Capricornids, and solution 199/02 to Northern delta-Capricornids. The relevant codes will be determined by the WG. Alternatively, the northern branch retains the original shower name and code. The WG will make the final decision.

202/ZCA Daytime zeta-Cancrids. The values of DH_Min = 0.434 and DH_MI = 0.039 clearly indicate that we are dealing with two different streams. Solutions 202/00 (Nilsson 1964b) and 202/01 (Brown et al. 2010) are the only ones we have in the MDC, coming from observations that are separated by an interval of ~40 years. The parameters of the 202/00 solution are not internally consistent. However, using the methodology proposed by Neslušan et al. (2024), we found a large difference only in the calculated value of the orbit inclination. Nilsson reports i = 21.1°, and according to our calculations i = 7°. Koseki (2016) also found a similar inconsistency in the parameters of the 202/00 solution; however, he states that in addition to the orbit inclination, the inconsistency also occurs for the argument of the perihelion of the orbits. Due to the lack of access to the data of individual members of both solutions, we cannot determine the reason for the inconsistency of solution 202/00. In view of the particularly large DH = 0.434 and its internal data inconsistency we propose to move solution 202/00 to the List of removed showers. Consequently, we propose cancelling the established status of 202/ZCA.

220/NDR nu-Draconids. The only solutions given in the MDC of this stream are 220/00 and 220/01. The first was identified by Sekanina (1976) among ~20 000 radio meteors, the second by Jenniskens et al. (2016b) among ~11 000 meteors observed by video technique. The value of DH_Min = 0.144 exceeds the acceptable value of DH_MI = 0.059, and the solutions differ the most in the inclination, DH_in = 0.101 and the orientation of the lines of the apses, H_Π = 0.093. Solutions were observed with different techniques, in different eras (40 years difference), so in view of the comments given in Section 3, DH_Min = 0.144 is not critical. Therefore, we do not propose to change the 220/00 and 220/01 solution status in the MDC.

233/OCC October Capricornids. The values of DH_Min = 0.160 and DH_MI = 0.039 indicate a possible misclassification of the 233/00 or 233/01 solutions. These are the only solutions for which orbital data is provided in the MDC, and the 233/OCC stream has an ‘established’ status with an IAU-approved name. The orbits of the two solutions differ practically only in the orientation of the apse lines, DH_Π = 0.151. They were determined by visual observations by Wood (1988) and photographic observations by Terentjeva (1989). The parameters of the 233/01 solution were obtained from averaging a number of (unfortunately unknown to us) orbits. The orbit of the 233/00 solution was obtained by means of estimating the position of the radiant and the out atmospheric velocity, for the date corresponding to the maximum of shower activity.

As described by Wood (1988), the existence of the 233/OCC stream is not in doubt, its activity was observed in 1971–1987. Another confirmation of its nature, especially the relatively high activity in 1972, was the return of comet Haneda-Campos (D/1978 R1) before its observation in 1978. The similarity of its orbit to that of the 233/00 solution was noted by Wood (1988). However, it is not the only object associated with this stream. Durišová et al. (2024) confirmed the similarity of 233/00 to the orbit of comet D/1978 R1, but also pointed out the similarity to the orbits of comets 15P and 103P. And according to Dumitru et al. (2017), the orbit of 233/OCC is also similar to the orbits of many near-Earth asteroids. Undoubtedly, the reason for so many potential parent bodies of 233/OCC streams is that its orbit has a slight inclination to the plane of the ecliptic. In view of the above, we propose that the current status of shower 233/OCC in the MDC database be maintained.

253/CMI December Canis Minorids. The values of DH_Min = 0.347 and DH_MI = 0.059 indicate a misclassification of the 253/00 or 253/03 solutions. Solutions were obtained from video observations, 253/00 by Jenniskens et al. (2016b), 253/03 by Shiba (2022). Both were identified in large orbital samples and they are the only solutions available in the MDC. The high value of the DH-function mainly originates from the orientation of the solutions’ orbits: DH_in = 0.195, DH_Π = 0.221.

As can be seen in Figure 23, the name Canis Minorids of this MSS is inconsistent with the old stream nomenclature rules. Both radiants are located outside of the constellation Canis Minor. However, in order to make as few changes to the MDC as possible, we recommend that both solutions remain in the MDC as separate streams: solution 253/00 with no changes in codes and name; solution 253/03 with new codes and name assigned by the WG.

254/PHO Phoenicids. The values of DH_Min = 0.199 and DH_MI = 0.039 indicate a possible misclassification of the 254/00 or 254/01 solutions. Phoenicids in MDC are represented by two solutions and have established status.

For the MDC, 254/00 solution was taken from Jenniskens (2006), who used the two orbits given by Cook (1973). Cook, in turn, used results given by Ridley (1962, 1963) who used visual observations and gave two orbits. The first was calculated as parabolic and the second was based on the similarity of the parabolic orbit with the orbit of comet 289P (formerly D/1819 W1 (Blanpain)). This elliptical orbit was calculated assuming that its orbital period is 5.1 years, the same as the orbit period of comet 289 P. So, it is not unusual that the similarity of the orbits of solution 254/00 and comet 289P was confirmed by Durišová et al. (2024). The 254/PHO stream parameters given by Jenniskens (2006), more likely obtained by averaging the data given by Cook (1973). Unfortunately, as noted in Table B.1, they are internally inconsistent. The 254/00 solution was given by Cook (1973) on the basis of visual observations. Solution 254/01 came from Shiba (2022), who identified only 9 members among ~300 000 video orbits. The orbits of these solutions differ markedly in inclination, DH_in = 0.184. But they are also clearly different in the radiant declination ΔDec = 37° and the radiant ecliptic longitude in the rotating reference frame Δλ_{RS C} = 33°.

Based solely on our methodology, we propose to give autonomous status: to solution 254/00 with no changes in codes and name; to solution 254/01 with new codes and name assigned by the WG. After excluding one solution, shower 254/PHO will not fulfil the condition for established status; therefore, we also suggest changing its status from established to working.

However, it is still possible that the different solutions of 254/PHO represent the same stream. A dynamical study by Kováčová et al. (2025) showed that meteoroids released from the proposed parent bodies of this shower (Durišová et al. 2024) move in highly perturbed orbits, resulting in a large dispersion of meteoroid orbits in their theoretical streams, and consequently reducing the compactness of the shower parameters. Therefore, the final decision should involve a more in-depth discussion within the WG, taking into account the results of dynamical studies related to this stream.

324/EPR epsilon-Perseids. The values of DH_Min = 0.250 and DH_MI = 0.059 indicate a possible misclassification of the 324/00 or 324/01 solution. Brown et al. (2008) identified 203 members of the 324/00 solution among more than 2 million orbits obtained over the period 2000–2006 radio survey. In contrast, Jenniskens et al. (2016a) identified only 4 members of the 324/01 solution among ~110 000 video orbits. The largest contribution to the DH_Min = 0.250 comes from the difference in the inclination of the orbits, DH_in = 0.211. The identification of the 324/00 stream is not in doubt, which cannot be said of the 324/01 stream. This MSS is represented by two solutions only, and has established status in the MDC. However, in the absence of other arguments, we propose that both 324/EPR stream solutions be given stand-alone status in the MDC. Solution 324/00 with an unchanged name and codes, solution 324/01 with a new name and codes fixed by the WG. Consequently, we propose moving 324/EPR to the Working list.

326/EPG epsilon-Pegasids. This MSS is represented by two solutions and has an established status in the MDC. The values of DH_Min = 0.175 and DH_MI = 0.059 indicate a problem with the correct classification of solutions 326/00 and 326/01. The first solution was identified by Brown et al. (2008) (62 members) among more than three million radio orbits, the second was given by Jenniskens et al. (2016a) (33 members) analysing ~ 110.000 video orbits. The orbits of these solutions differ mainly in inclination, DH_in = 0.125. In the absence of other arguments, we propose that both 326/EPR stream solutions be given a standalone status in the MDC. We propose that solution 326/00 retain its current name and codes, while a new name and code be assigned to solution 326/01 by the WG. After separation, the conditions for the shower established status will not be sufficient, so both solutions will be moved to the Working list.

327/BEQ beta-Equuleids. The values of DH_Min = 0.377 and DH_MI = 0.059 indicate misclassification of one of the 327/00 or 327/01 solutions. They are the only solutions of the beta-Equuleids shower included in the MDC database. 327/00 identified by Brown et al. (2008), 89 members from three million radio data, has a radiant located near the star beta-Equulei. Solution 327/01 given by Jenniskens et al. (2016a), 38 members from ~110 000 video orbits, has a radiant in the constellation Aquila, near the star theta-Aquilae, see Figure 24. The orbits of these solutions differ mainly in inclination, DH_in = 0.282, and orientation of the apse line, DH_Π = 0.247. In addition, their radiants are located at a considerable distance from each other, which is also noted by Koseki (2020). However, in the case of 327/BEQ solutions, the components of diurnal motion of the radiants given in the source documents do not allow to reconcile the positions of these radiants. The reason lies in the opposite signs of the radiant’s diurnal motion in the declination component. The large values DH_Min = 0.377 of the discussed shower indicate the absence of a genetic connection for these solutions, for which we also failed to find the parent comet; (see Durišová et al. 2024). We therefore propose that both solutions be given stand-alone status: 327/00 without the code and name change, while 327/01 with a new code and designation. Both solutions will be moved to the Working list as stand-alone showers since they will no longer meet the conditions for the established status.

334/DAD December alpha-Draconids. The values of DH_Min = 0.110 and DH_MI = 0.059 indicate some problem to classify the solutions of this stream. Solution 334/01 identified by Jenniskens et al. (2016a), 47 members among ~100 000 video data, 334/03 found by Shiba (2022), 487 members among ~230 000 video orbits. The mean orbits differ mainly in the inclination and orientation of the apse line, DH_in = 0.068 and DH_Π = 0.078. But these are not big differences. The radiants of both solutions are located in the constellation of Ursa Major.

Another solution to this stream, 334/00 obtained by SonotaCo (2009), 145 members among 240 000 video observations, is given in MDC. However, SonotaCo (2009) did not provide the mean orbital data of this shower. But for the purposes of our study we calculated this orbit using the geocentric data of this solution. We applied an approach analogous to that used by Brown et al. (2008), who computed the mean orbits using the radiant and velocity observed at the time of maximum shower activity. The calculated orbit of the 334/00 solution turned out to be more similar to that of 334/03, DH_P = 0.084, also the application of the maximum sigma method yielded a positive result for this pair. Repeating the cluster analysis calculations for the three members of 334/DAD also yielded a positive result, DH_Min = 0.108, with an acceptable threshold value of DH_MI = 0.136. This means that we have no grounds to change anything in the MSS 334/DAD status.

347/BPG beta-Pegasids. The values of DH_Min = 0.230 and DH_MI = 0.059 indicate a problem with the correct clarification of solutions 347/00 or 347/01. These are the only solutions for this stream in the MDC. The first was identified among three million radio orbits by Brown et al. (2010), 1105 members. The second was reported by Jenniskens et al. (2016b), 11 members, identified amongst ~110 000 video orbits. The orbits of these solutions differ mainly in inclination DH_in = 0.150 and orientation of the apse line DH_Π = 0.131. Both radiants are located in the constellation Pegasus. In view of the large DH=0.230 value, our recommendation is to split this MSS into two stand-alone solutions, with 347/00 keeping its current name and codes, and 347/01 receiving new ones.

372/PPS phi-Piscids. The stream has an ‘established’ status officially granted by the IAU. However, the values of DH_Min = 0.350 and DH_MI = 0.059 indicate a misclassification of its solutions 372/00 or 372/02. In our study, 372/PPS is represented by two solutions obtained from radio observations by Brown et al. (2010), 1395 members, and from video observations by Jenniskens et al. (2016a), 379 members. The orbits of these solutions differ in eccentricity and orientation of the apse line, DH_e = 0.292 and DH_Π = 0.187. Following the completion of our research published in Paper I, Shiba (2023) identified 358 members among 126184 video orbits belonging to this shower; the solution was added to the MDC with the codes 372/PPS/04. It is closer to solution 372/02, DH_P = 0.085. However, when the 372/04 solution was incorporated into the 372/00, 372/02 pair, it became apparent that the identification of this group as representing the 372/PPS stream still required a value of DH_Min = 0.350. This justifies the claim that solution 372/00 should be recognised as a separate stream, while solutions 372/02 and 372/04 represent the same 372/PPS stream.

The meteoroids included in solutions 372/02 and 372/04 were observed, in different years, for almost 2.5 months, from early June to first half August. In the case of 372/00, observations were made on several days in early July only. This may suggest that the radio sample of 1395 orbits was obtained from a different part of the 372/PPS stream than the video observations. With the recently introduced requirement to provide the MDC with stream averaged parameters (see Jenniskens et al. (2020)), data of its members, we have access to the geocentric parameters of the members of the 372/04 solution.

Using these data, we calculated the orbital elements of the members of this solution, the two distributions of these elements are illustrated in Figure 25, where the points corresponding to the members of the 372/04 stream and the average values of the 372/00 solution are plotted.

This figure leads to the conclusion that the 372/00 solution does not represent the same stream as the 372/04 solution. In particular, the 1 / Q versus inc diagram (inverse of the distance of the aphelion versus the inclination of the orbit) shows that these solutions have different parent bodies. Stream 372/04 lies in an area dominated by comets (see Jopek et al. (2024)) while stream 372/00 lies in an area devoid of comets. Hence, we propose that solution 372/00 be given stand-alone status with a new name and codes, while solutions 372/02 and 372/04 be left unchanged in the MDC. We also suggest reconsidering the established status of 372/PPS.

386/OBC October beta-Camelopardalids. The values of DH_Min = 0.266 and DH_MI = 0.059 indicate misclassification of its only solutions 386/00 or 386/01. Solution 386/00 obtained from radio observations by Brown et al. (2010), 355 members, and 386/01 from video observations by Jenniskens et al. (2016b), 28 members. The radiant of solution 386/01 is situated in the constellation of Perseus. The mean orbits of the two solutions differ mainly in their inclination to the plane of the ecliptic, DH_in = 0.260. Other differences are negligible contributors. A considerable difference of about 6 degrees is in λ_{S RC}. All of this argues in favour of giving both solutions stand-alone stream status in the MDC, with 368/00 retaining its current name and codes. Solution 386/01 will be assigned new IAU MDC codes and a new name corresponding to its radiant position.

392/NID November i-Draconids. Brown et al. (2010), among radio orbits, identified 2059 members of the 392/00 stream. Jenniskens et al. (2016a), among video orbits, found 65 members of the 392/01 solution. The values DH_Min = 0.317 and DH_MI = 0.059 suggest that these solutions do not represent the same stream. The reason for this lies in the large value of the components DH_in = 0.227 and DH_Π = 0.222, the differences in the inclination of the orbits and the orientation of the apse lines.

The geo-helio parameters of the 392/01 solution are inconsistent, problematic is the value of the longitude of the ascending node Ω = 254.4°. This inconsistency was also noted by Koseki (2020). Using Ω = 242.0° removes the incompatibility; however, the new calculated value of DH_Min = 0.182 is still too large to consider both solutions as representing the same stream. Also, the MSM method test resulted in the same conclusion.

However, it is still a problem of rather large difference of 9° in the λ_{RS C} of the two solutions, which in this case cannot be explained by the diurnal motion of the two radiants. The values of the Sun’s ecliptic longitudes λ_S differ by only 1 degree.

The 392/NID stream was discovered and sent to MDC by Brown et al. (2010) who noted that it has similar parameters to the 10/QUA stream. The authors write “... a surprising finding from our survey is an apparently new shower (NID) that appears to be directly associated with the Quadrantids. The NID has the same radiant location (in ecliptic coordinates) and speed as the QUA and both have overlapping periods of activity. Indeed, our automatic algorithm linked portions of the showers as though they were a single long-duration shower, extending the QUA period of activity into November. From our observations, we interpret the NID as simply an early extension of the QUA.” This remark suggests that we may be dealing with a more complex structure in the case of 392/NID. A similar comment is made by Koseki, who believes that the stream may be an earlier activity of 334/DAD. Jenniskens (2023) consider 392/NID as the central part of a larger complex including showers 334/DAD and 336/DKD. However, this problem is beyond the scope of our current research. Therefore, we propose that both solutions 392/00 and 392/01, should represent separate streams in MDC, with the first solution retaining the name and codes. The WG’s final decision may require a detailed discussion.

490/DGE December delta-Eridanids. Both solutions come from video-observed meteor sightings. 490/00 was identified among a combined sample of orbits (64650+40744) determined by the SonotaCo consortium in Japan from 2007–2009 and by the Cameras for All-sky Meteor Surveillance (CAMS) project in California from October 2009 to December 2011. Rudawska & Jenniskens (2014) identified 7 members of the stream. The 490/01 solution (20 members) was obtained by Jenniskens & Nénon (2016), among an enlarged combined sample of 168 000 SonotaCo and 238 000 CAMS orbits. It is clear from Jenniskens & Nénon (2016) that the subsequent augmented sample of orbits included the data used to identify the 490/00 solution. This means that the two solutions cannot be considered independent representations of the 490/DGE stream. The DH_Min = 0.149 and DH_MI = 0.039, the main difference takes place in the orientation of the apse lines of the two orbits, DH_Π = 0.137. We are unable to pinpoint the reason for this difference. Hence, according to the adopted methodology, these solutions should be considered autonomous. However, in view of the fact that both come from samples of orbits one of which is contained in the other, and especially the moderate value of the DH-function we leave the problem of justifying a proper recommendation as open.

507/UAN upsilon-Andromedids. The first 507/00 solution was obtained from video observations (CAMS) over a two-month period from June 2 to August 7, 2011. Holman & Jenniskens (2013) identified 13 members of the stream. The second solution 507/001, obtained from 28 members, Jenniskens et al. (2016c) identified among 110 000 orbits determined from CAMS observations from October 2010 to March 2013. Thus, it appears that solution 507/00 was obtained from a sample included in the sample in which solution 507/01 was identified.

The DH_Min = 0.326 and DH_MI = 0.039 clearly suggest incorrect classification of at least one of the solutions. The mean orbits differ mainly by perihelion distances DH_q = 0.106 and by orientation of the line of apse DH_Π = 0.299. The reason for such a large value of DH_Π is the difference in the argument of the perihelion of the two orbits, Δω ~ 20°. Unfortunately, we do not have the data of the members of these solutions at our disposal, so it is difficult to give reasons for this discrepancy. Hence, due to the extremely large value of DH_Min = 0.326, we propose that they will obtain a status of autonomous streams in MDC, with solution 507/00 retaining the current name and codes.

512/RPU rho-Puppids. Stream 512/00, with 16 members, was identified by Segon et al. (2013) among 10645 video meteors observed from 2007–2010 by the Croatian Meteor Network and among video meteors observed from 2007–2011 by the SonotaCo consortium. Stream 512/01, with 22 members, was identified by Jenniskens et al. (2016b) among 110 000 meteors observed from 2010–2013 by the CAMS project. For these solutions, DH_Min = 0.370, DH_MI = 0.059 which suggests a misclassification of one of them. The mean orbits differ mainly in the inclination DH_in = 0.131, and in the orientation of the apse line DH_Π = 0.346.

After the end of December 2022, Shiba (2023) delivered another solution 512/03 to the MDC. Shiba searched the video orbits from the SonotaCo consortium catalogues. After incorporating this solution with the two others, it turned out that they could be identified at DH_Min = 0.202 and the 512/03 solution is more similar to 512/00 than to 512/01. The corresponding value DH_Π = 0.174, with the greatest contribution from the orientation in the apse line DH_Π = 0.152. We do not have access to the orbital data of the members of the 512/01 solution, which would allow for a more detailed analysis of the reason for its difference from the other solutions. But we think that some reason may be that Jenniskens et al. (2016b) reported the median values as the mean parameters of his solution, and Segon et al. (2013) and Shiba (2023) reported the arithmetic mean values of the stream members’ parameters.

According to Segon et al. (2013), the parent body of the 512/RPU is most likely comet C/ 1879 M1. This conclusion was confirmed by Durišová et al. (2024) for the solution 512/00 not for 512/01. It is an important argument when it comes to the feasibility of this stream. Because of this we propose an autonomous status for the 512/01 solution, whose radiant is located in the Pyxis constellation, and retaining the 512/00 solution as the representative of the 512/RPU shower. In spite of excluding one of the shower solutions, due to the recent submission by Shiba (2023), the established status of the shower does not need to be reconsidered.

555/OCP October gamma-Camelopardalids. The values of DH_Min = 0.282 and DH_MI = 0.059 indicate an incorrect classification of at least one of the solutions. Both solutions 555/00 and 555/01 were identified among the meteors observed by the video technique using the same orbital samples as for the 512/RPU stream discussed earlier. Stream 555/00, with 16 members, was identified by Andreić et al. (2014), stream 555/01, with 14 members, was identified by Jenniskens et al. (2016b). The solutions differ practically only in the orientation of the apse line, DH_Π = 0.273. This large DH_Π value is the result of a 17-degree difference in the perihelion argument of the mean orbits. As in the case discussed earlier, the mean values of the parameters of these solutions were obtained by different methods, in solution 555/00 the arithmetic means were taken, in solution 555/01 the medians were taken. In the case of the asymmetric nature of the distribution of the parameters, this can lead to marked differences in the averaged values. We do not have access to the parameter values of the members of the two solutions, which prevents further analysis of this case. We therefore propose that solutions 555/00 and 555/01 be given autonomous status in MDC, with 555/00 retaining its current name and codes, while 555/01 being assigned new IAU MDC codes and a new name corresponding to its radiant position.

574/GMA gamma-Ursae Majoris. Both solutions were identified among the meteors observed with video technology. Gural et al. (2014) identified 21 members of solution 574/00 among orbits observed from 2007 to 2010 by Croatian Meteor Network and among orbits observed from 2007 to 2011 by SonotaCo consortium. Shiba (2022) found 15 members of solution 574/01 among 298 689 orbits observed in the interval 2007–2020 by SonotaCo Network. Although Gural et al. (2014) does not specify the size of the sample searched, it can be deduced that they searched among more than 100 000 SonotaCo orbits. So the two obtained solutions of the 574/GAM stream, probably are not fully independent. In view of the small number of members identified, we can conclude that the 574/GMA solutions indicate that we are dealing with a very faint stream.

DH_Min = 0.480 and DH_MI = 0.059, so there is undoubtedly a misclassification of at least one of the solutions. The large value of DH_Min for these orbits is the result of large contributors in DH_e = 0.186, DH_in = 0.117 and especially in DH_Π = 0.425, i.e. due to significant differences in eccentricity, inclination and in the orientation of their apse lines.

We propose that both solutions should be considered as solutions of different streams. Solution 574/00 has a radiant close to star gamma-Ursae Majoris, so we can leave it in the MDC with unchanged codes and name. On the other hand, solution 574/1, with a radiant near the star 5-Canum Venaticorum must be given stand-alone status with a new designation.

644/JLL January lambda-Leonids. DH_Min = 0.256 and DH_MI = 0.039, thus, the correctness of the classification test of the 644/00 and 644/02 solutions of this stream turned out to be negative. Both solutions were determined using video meteor observations. In the first case, Jenniskens et al. (2016c) identified 24 meteoroids among 110 000 orbits, while in the second case, Shiba (2022) identified 172 members among 298 000 orbits.

The internal data consistency test of the 644/00 solution came out negative. The critical contribution in the assessment of orbital similarity is due to the orientation of the apse lines of the two orbits DH_Π = 0.228. Which, in turn, has its source in the incompatibility of the ecliptic longitude of the Sun, λ_S = 288.0°, and the longitude of the ascending node Ω = 277.7° in the 644/00. In our opinion, as also noted by Koseki (2016), the longitude of the ascending node should be 287.7° instead of 277.7°. Substituting this value in the intrinsic consistency test yielded a positive result for this solution. The introduced correction of the longitude of the ascending node clearly decreased the value DH_Min = 0.121.

We do not have access to the individual data of members of the 644/00 and 644/02 streams to make a direct comparison and assess the impact of averaging methods on their orbital similarity. In the 644/00 solution, Jenniskens et al. (2016c) reports the medians of the parameters. Shiba (2022) calculated the arithmetic averages. The 644/00 stream activity lasted about 25 days, which means that the median values of the 24 members may not be sufficiently representative. Hence, it can be assumed that the DH_Min = 0.121 value has some degree of variation due to the method used to average the stream parameters. Thus, we believe that the 644/00 and 644/02 solutions do not require any change in MDC.

709/LCM lambda-Canis Majorids. Both solutions to this stream were determined by the same authors and in the same video data samples as in the 644/JLL case. Jenniskens et al. (2016c) identified 18 members in 709/00, while Shiba (2022) found 192 in 709/01. The values DH_Min = 0.142, DH_Mi = 0.039, formally, suggest a problem in the correctness of the classification of the two solutions. The greatest contribution comes from the inclination of the orbits, DH_in = 0.132. For both solutions, the internal data compatibility test was very positive. Hence, without access to the data of the members of the streams, we are unable to pinpoint the reason for the divergence of their mean orbits. In view of the rather small discrepancy, we propose leaving 709/00 and 709/01 unchanged in the MDC despite the fact that radiant 709/01 is located in the constellation Lepus, relatively far from the star λ Canis Majoris.

1048/JAS January psi-Scorpiids. DH_Min = 0.150 and DH_Mi = 0.059 indicate a discrepancy between solutions 1048/00 and 1048/01. Among those discussed previously, the case of the 1048/JAS stream is an exception. Both solutions were obtained using predictions of the stream parameters obtained from studies of the dynamic evolution of comet C/1936 O1, see Hajduková & Neslušan (2021). The authors compared the parameters of the orbits of the hypothetical streams with the orbits of individual meteoroids collected in the IAU MDC Orbital Database⁵. Two groups of orbits were identified, the parent body of which could be comet C/1936 O. Solution 1048/00 has ten members found by Hajduková & Neslušan in the CAMS (Gural 2011; Jenniskens et al. 2011, 2016a,b; Jenniskens & Nénon 2016; Jenniskens et al. 2016c) and 1048/01 eight members in the SonotaCo database (SonotaCo 2009, 2016, 2017; SonotaCo et al. 2021), IAU MDC version 2013. The discrepancy in the parameters of the orbits of these solutions has its origin mainly in the inclination of the orbital planes DH_in = 0.120. Since 1048/JAS is a daytime shower (the angular distance of its mean radiant from the Sun at maximum activity is 52°) with a high mean inclination (i ~ 144° to ~151°), the meteoroids having a large geocentric speed of 60 km s⁻¹ (Hajduková & Neslušan 2021), and the significant difference of various parts of the stream was predicted by the simulation performed by these authors, we suggest to keep both solutions unchanged.

Fig. 8 Positions of the radiants of two solutions of shower 76/KAQ (red asterisks). The closest star to the 76/KAQ/00 solution is 45-Aquarii and to 76/KAQ/01 is κ-Aquarii (cyan full circles). The violet curve shows the ecliptic. The radiants of the solutions are located on both, northern and southern, ecliptic celestial hemispheres.

Fig. 9 Positions of the radiants of two solutions of shower 93/VEL (red asterisks). The closest star to the 93/VEL/00 solution is upsilon Carinae, and for the 92/VEL/01 solution, it is δ-Velorum (cyan full circles).

Fig. 10 Radiants of two solutions of shower 105/OCN (red asterisks). The closest star to both radiants is θ-Carinae.

Fig. 11 Radiants of two solutions of shower 106/API (red asterisks). The radiant of 106/API/00 shower is close to star δ-Volantis, and the radiant of 106/API/01 is close to the star α-Mensae.

Fig. 12 Radiants of two solutions of shower 108/BTU (red asterisks). The radiant of 108/BTU/00 shower is close to star ι-Hydri, and the radiant of 108/BTU/01 is close to the star ν-Mensae.

Fig. 13 Radiants of two solutions of shower 113/SDL (red asterisks). The radiant of 113/SDL/00 shower is close to star π1-Cancri, and the radiant of 113/SDL/01 is close to the star ω-Hydrae. The purple curve is the ecliptic.

Fig. 14 Radiants of two solutions of shower 124/SVI (red asterisks). The radiant of 124/SVI/00 shower is close to star η-Virginis, and the radiant of 124/SVI/01 is close to the star ϵ-Leonis.

Fig. 15 Radiants of solutions of 133/PUM shower (red asterisks). The radiant of 133/0 shower is located in the constellation Lynx, close to star 27-Lyncis. The radiant of 133/1, located in constellation Ursae Majoris, is close to the star ϕ-Ursae Majoris.

Fig. 16 Radiants of solutions of 150/SOP shower (red asterisks). The radiant of 150/SOP/01 shower is located in the constellation Ophiuchus. The radiant of 150/SOP/08, located in constellation Scorpius, is close to the star π-Scorpii.

Fig. 17 Radiants of solutions of 151/EAU shower (red asterisks). The radiant of 151/EAU/00 shower is located in the constellation Aquila near the star ε-Aquilae. The radiant of 151/EAU/01, located in constellation Vulpecula, is close to the star 9-Vulpeculae.

Fig. 18 Radiants of solutions of 167/NSS shower (red asterisks). The radiant of 167/00 shower is located in the constellation Sagittarius near the star 55 Sagittarii. The radiant of 167/01 is located in the same constellation close to the star 21 Sagittarii.

Fig. 19 Radiants of solutions of 170/JBO shower (red asterisks). The radiant of 170/00 shower is located in the constellation Draconis near the star α-Draconis. The radiant of 170/04 is located in the Bootes constellation close to the star 44-Bootis.

Fig. 20 Radiants of solutions of 179/SCA shower (red asterisks). The radiant of 179/00 shower is located in the constellation Capricornus near the star ϵ-Capricorni. The radiant of 179/01 is located in the Aquarius constellation close to the star v-Aquarii.

Fig. 21 Radiants of solutions of 186/EUM shower (red asterisks). The radiant of 186/00 shower is located near the star ε-Ursae-Majoris. The radiant of 186/01 is located in the constellation Draco close to the star ι-Draconis.

Fig. 22 Radiants of solutions of 189/DMC shower (red asterisks). The radiant of 189/00 shower is located in the constellation Cancer near the star μ1-Cancri. The radiant of 189/01 is located in the Gemini constellation close to the star 52-Geminorum.

Fig. 23 Radiants of solutions of 253/CMI shower (red asterisks). The radiant of 253/00 shower is located in the constellation Gemini, the radiant of 253/03 is located in the constellation Cancer.

Fig. 24 Radiants of solutions of 327/BEQ shower (red asterisks). The radiant of 327/00 shower is located in the constellation Equuleus, and the radiant of 327/01 is located in the constellation Aquila.

Fig. 25 Distributions of e versus λS and 1 / Q versus inc (inverse of the distance of the aphelion versus the inclination of the orbit), 358 members of the 372/04 stream (green), and two points corresponding to the average values of the 372/04 (black) and 372/00 (red) solution. The mean values of the eccentricities of the two solutions are definitely different from each other. In the figure on the right, solution 372/00 belongs to the area to which known comets belong. Solution 372/00 is located in an area where known comets do not exist.

5 False duplicates and search for the parent bodies

It is worth noting that false duplicates cause a problem when searching for the parent body of the meteoroid stream. It may occur that a comet or asteroid can be identified as the parent associated with some solutions of a stream but cannot be identified with the other solution or solutions of the stream. Usually, this problematic identification is caused by false duplicates.

In our previous paper (Durišová et al. 2024), we searched for the parent bodies of known meteor showers, with known mean orbits, and found several examples of problematic parent-body identifications. These examples include not only the new associations discovered by the method we used, but also the suggestions published in the literature. Several illustrative examples of the problematic identification are given below.

Apart from these examples, the parent comets of 56 investigated problematic MSSs are given as found for the individual solutions in the last column of Table B.1. In some cases, a given parent comet was found for one solution, but not confirmed for another solution. This circumstance can also help distinguish between the duplicate and false duplicate showers.

11/EVI. Jenniskens (2006) suggested that comet D/1766 G1 is the parent body of shower η-Virginids, 11/EVI. We confirmed this suggestion with our method, but only for solution 11/01; see Durišová et al. (2024). The solutions 11/00 and 11/06 were not found to be associated with the comet; see Table B.1. Which, in our opinion, supports the finding that the solutions given in Table B.1 not represent the same 11/EVI stream.

113/SDL. In Durišová et al. (2024) solution 113/00 was associated with comet 26 P, but the comet does not share a relation with 113/01, which further supports our decision to consider the two solutions as separate showers.

133/PUM. Here again, the proposed decision of splitting the solution of shower 133/PUM is supported by our parent body search, as only solution 133/00 was associated with comet 79P. Upon splitting the solutions, the association with the comet is valid only for the Terentjeva’s stream.

152/NOC. For 152/NOC, Jenniskens (2006) suggested an association with C/2003 Q1 for this MSS. However, in Durišová et al. (2024) we have not confirmed this relationship for any of the three solutions of the 152/NOC stream.

199/ADC. Considering shower 199/ADC, the comet 45P was identified in Durišová et al. (2024) as a parent body for solutions 199/00 and 199/02. This finding confirms the hypothesis of a common origin of the two 199/ACD solutions, while at the same time not denying that solutions 199/00 and 199/02 correspond to two branches of this stream, see Section 4.2.

233/OCC. For the October Capricornids we are dealing with a more complex case. We confirmed the relationship between the 233/00 solution and comet D/1978 R1, already proposed by Wood (1988). But this comet was not associated with solution 233/01. Moreover, we found that solution 233/00 is also related with comet 15P/Finlay. Solution 233/01 is not associated with this comet, but is associated with comets 11P/Tempel-Swift-LINEAR, 85D/Boethin and 103P/Hartley 2; see Durišová et al. (2024). We also note that Dumitru et al. (2017) has identified many near-Earth asteroids associated with the 233/OCC stream, which undoubtedly means that we have a particularly complex group of objects here.

254/PHO. Also the case of stream 254/PHO is more complicated. Durišová et al. (2024) showed that the orbits of three comets are similar to the orbits of the 254/PHO solutions: 289 P, 46 P and 104P, see Table B.1. The connection between the comet 289P and the stream was investigated by several dynamical studies. Kasuga (2025) proposed that the comet is a remnant of a sub-km predecessor body as its activity is insufficient to account for the stream’s mass. Alternatively, Sato et al. (2017) suggested that the comet is turning dormant. Recently, Kováčová et al. (2025) tried to answer the question which one of comets 46P, 104P, and 289P is the parent body of the Phoenicid shower. They found that there is a preference for 289P to be the parent body (but only of the solution 254/01) from the dynamical point of view. However, the nucleus of 289 P is too small to produce the observed Phoenicid stream. They speculated that this nucleus might rather be a large Phoenicid meteoroid than the stream’s parent.

Thus, we have an unusual situation: basically, in the 254/PHO stream, both its autonomous (in our opinion) solutions come from three different comets, or from any of these comets. Kováčová et al. (2025) tried to resolve this question. However, no rigorous answer appeared to be possible.

512/RPU. Solutions 512/00 and of the ρ-Puppids, 512/RPU, were confirmed to be associated with comet C/1879 M1, but this association was not confirmed for solution 512/01.

6 Conclusion and future action

All partial conclusions are summarized and future action is proposed in Table A.1. It serves as a proposal for decision-making under the WG of the IAU commission F1.

The research we conducted in Paper I revealed that some of the 1182 meteor shower solutions given in the MDC database were unfortunately misclassified. The presence of misclassified meteor showers degrades the database’s quality, and the use of erroneous data can lead to the generation of artefacts. The methodology used in Paper I allowed us to conclude that among the 56 meteor showers represented by two or more solutions, most likely there is a misclassification of solutions. The reason for this is, among other things, the lack of criteria to properly decide whether the new meteoroid data provided to the IAU MDC represent a newly discovered meteoroid stream or another representation of an already known meteoroid stream.

In the present work, we examined the results from Paper I in greater detail and assessed the individual cases from various aspects. We relied on comparing the averaged geocentric and heliocentric parameters of meteoroid streams and the relationship of the streams with their parent comets. As a result of the methodology used, taking into account its limitations listed in Section 3, we considered 13 of 56 MSSs to be correctly classified. We identified 43 showers as requiring reclassification, including formal assignment of new names and codes to them by the IAU WG. Among them are 11 cases of showers with an established status, which will need to be re-qualified from established back to working status. Table A.1 lists all the showers and their solutions that require correction.

In our research, we also encountered typographical errors in the data; some of them had already been noted by other authors. Table A.1 lists such cases while giving the correct values of the erroneous data to be entered into the IAU MDC database.

Although our study is not ‘definitive’, it clearly shows that in the past there has been repeated misclassification of new meteoroid streams delivered to the MDC. To avoid such errors, we propose that, based on the methods used in Paper I, a tool be made available on the MDC website to allow for comparison of new stream parameters with the contents of the database.

In Section 3, we list some of the reasons why two sets of averaged parameters of the same meteoroid stream may differ from each other. Large values of differences in parameters unquestionably indicate misclassification of at least one of the compared solutions. However, as we have seen in our research, assessing the correctness of the classification of meteoroid streams based only on their averaged parameters is not always possible. In such cases, it is invaluable to access the parameter values of all members of the stream. Therefore, we consider the requirement (see Hajduková et al. 2023) that authors should also provide data of the members of the stream when they provide new averaged data to the IAU MDC to be a very useful move. Having at one’s disposal the parameter values of individual meteoroids allows for a more objective classification of the stream they represent.

Finally, we would like to expressly emphasize that the research results presented here only deal with the problem of misclassification of different solutions of the same stream. Thus, the results of our research should not be considered as prejudging the existence or non-existence of a given stream.

Acknowledgements

This work was supported, in part, by VEGA – the Slovak Grant Agency for Science, grant No. 2/0009/22. The research has also made use of the Astrophysics Data System, funded by NASA under Cooperative Agreement 80NSSC21M00561. Excerpts from this work were translated and had their grammar corrected using DeepL.com and ChatGPT (free versions).

Appendix A Proposal for the re-qualification of individual meteor shower solutions

Appendix B Meteoroid stream parameters

Table B.1 lists the geocentric and heliocentric parameters of the multi-solution meteoroid streams from the IAU MDC database, among which false duplicates are possible. The data was grouped into three sections. The first contains data of 3 streams for which the possibility of false duplicates is only of a formal nature; see Section 3.

Appendix C Values of the DH orbital similarity function

Table C.1 gives the values of the DH function of the orbital similarity, and their individual components for pairs of orbits listed in Table B.1. Given the Keplerian elements of the orbits S1 and S2 — eccentricity e, perihelion distance q, inclination i, argument of perihelion ω, and longitude of the ascending node Ω — the corresponding orbital similarity value DH_P is given by the formula $$\begin{array}{rl}D{H}_P^2=& D{H}_e^2+D{H}_q^2+D{H}_{in}^2+D{H}_{\mathrm{\Pi }}^2=\\ =& {[e_1-e_2]}^2+{\left[\frac{q_1-q_2}{q_1+q_2}\right]}^2+{[2\cdot \sin \frac{I_{12}}{2}]}^2\\ & +{\left[\frac{e_1+e_2}{2}\right]}^2{[2\cdot \sin \frac{{\mathrm{\Pi }}_{12}}{2}]}^2.\end{array}$$(C.1)

Here, I₁₂ is the angle between the two orbital planes and Π₁₂ is the difference of the longitudes of perihelia measured from the intersection point of the orbits, namely: $$\begin{array}{rl}& {[2\sin \frac{I_{12}}{2}]}^2={[2\sin \frac{i_1-i_2}{2}]}^2+\sin i_1\sin i_2{[2\sin \frac{{\mathrm{\Omega }}_1-{\mathrm{\Omega }}_2}{2}]}^2,\\ & {\mathrm{\Pi }}_{12}=({\omega }_1-{\omega }_2)+2\arcsin [\cos \frac{i_1+i_2}{2}\cdot \sin \frac{{\mathrm{\Omega }}_1-{\mathrm{\Omega }}_2}{2}\cdot \sec \frac{I_{12}}{2}].\end{array}$$(C.2)

When |Ω₁ − Ω₂|> 180°, the sign of arcsin should be opposite.

References

All Tables

All Figures

	Fig. 1 Positions of radiants (depicted by red asterisks) of the three solutions of 11/EVI shower. The star η-Virginis is shown with a cyan circle, and the positions of the other stars are shown with black circles.
In the text

	Fig. 2 Positions of radiants (depicted by red asterisks) of three solutions of shower delta-Chamaeleontids, 107/DCH. The position of double star δ-Chamaeleontis is shown with a cyan circle; the positions of the other stars are shown with black circles.
In the text

	Fig. 3 Positions of the radiants of three solutions of shower 121/NHY nu-Hydrids (red asterisks). The originally published erroneous position of the solution 121/0 is shown with the orange asterisk. The purple line shows the ecliptic. Stars v-Hydrae, ρ-Leonis, and δ-Crateris are plotted with the cyan circles. The other stars are shown with black circles.
In the text

	Fig. 4 Positions of the radiants of four solutions of shower 152/NOC Northern Daytime omega-Cetids (red asterisks). One can see that no solution is located in the constellation Cetus, however. The stars are depicted with black circles. The purple curve indicates the ecliptic.
In the text

	Fig. 5 Positions of the radiants of three solutions of shower 183/PAU Piscis Austrinids (red asterisks). Only the solution 183/PAU/00 is located in the constellation Piscis Austrinus. Two other solutions, 183/PAU/01 and 183/PAU/04, are located in the constellation Aquarius. The stars are depicted with black circles.
In the text

	Fig. 6 Positions of the radiants of three solutions of shower 188/XRI xi-Orionids (red asterisks). Stars ξ-Orionis and γ-Geminorum are plotted with the cyan circles; the other stars are shown with black circles.
In the text

	Fig. 7 Positions of four soof the radiants lutions of shower 219/SAR September mu-Arietids (red asterisks). Stars μ-Arietis, γ-Arietis, ρ-Piscium, 97-Piscium, 87-Piscium, and π-Piscium are shown with cyan circles. The other stars are depicted with black circles. The purple curve indicates the ecliptic.
In the text

	Fig. 8 Positions of the radiants of two solutions of shower 76/KAQ (red asterisks). The closest star to the 76/KAQ/00 solution is 45-Aquarii and to 76/KAQ/01 is κ-Aquarii (cyan full circles). The violet curve shows the ecliptic. The radiants of the solutions are located on both, northern and southern, ecliptic celestial hemispheres.
In the text

	Fig. 9 Positions of the radiants of two solutions of shower 93/VEL (red asterisks). The closest star to the 93/VEL/00 solution is upsilon Carinae, and for the 92/VEL/01 solution, it is δ-Velorum (cyan full circles).
In the text

	Fig. 10 Radiants of two solutions of shower 105/OCN (red asterisks). The closest star to both radiants is θ-Carinae.
In the text

	Fig. 11 Radiants of two solutions of shower 106/API (red asterisks). The radiant of 106/API/00 shower is close to star δ-Volantis, and the radiant of 106/API/01 is close to the star α-Mensae.
In the text

	Fig. 12 Radiants of two solutions of shower 108/BTU (red asterisks). The radiant of 108/BTU/00 shower is close to star ι-Hydri, and the radiant of 108/BTU/01 is close to the star ν-Mensae.
In the text

	Fig. 13 Radiants of two solutions of shower 113/SDL (red asterisks). The radiant of 113/SDL/00 shower is close to star π1-Cancri, and the radiant of 113/SDL/01 is close to the star ω-Hydrae. The purple curve is the ecliptic.
In the text

	Fig. 14 Radiants of two solutions of shower 124/SVI (red asterisks). The radiant of 124/SVI/00 shower is close to star η-Virginis, and the radiant of 124/SVI/01 is close to the star ϵ-Leonis.
In the text

	Fig. 15 Radiants of solutions of 133/PUM shower (red asterisks). The radiant of 133/0 shower is located in the constellation Lynx, close to star 27-Lyncis. The radiant of 133/1, located in constellation Ursae Majoris, is close to the star ϕ-Ursae Majoris.
In the text

	Fig. 16 Radiants of solutions of 150/SOP shower (red asterisks). The radiant of 150/SOP/01 shower is located in the constellation Ophiuchus. The radiant of 150/SOP/08, located in constellation Scorpius, is close to the star π-Scorpii.
In the text

	Fig. 17 Radiants of solutions of 151/EAU shower (red asterisks). The radiant of 151/EAU/00 shower is located in the constellation Aquila near the star ε-Aquilae. The radiant of 151/EAU/01, located in constellation Vulpecula, is close to the star 9-Vulpeculae.
In the text

	Fig. 18 Radiants of solutions of 167/NSS shower (red asterisks). The radiant of 167/00 shower is located in the constellation Sagittarius near the star 55 Sagittarii. The radiant of 167/01 is located in the same constellation close to the star 21 Sagittarii.
In the text

	Fig. 19 Radiants of solutions of 170/JBO shower (red asterisks). The radiant of 170/00 shower is located in the constellation Draconis near the star α-Draconis. The radiant of 170/04 is located in the Bootes constellation close to the star 44-Bootis.
In the text

	Fig. 20 Radiants of solutions of 179/SCA shower (red asterisks). The radiant of 179/00 shower is located in the constellation Capricornus near the star ϵ-Capricorni. The radiant of 179/01 is located in the Aquarius constellation close to the star v-Aquarii.
In the text

	Fig. 21 Radiants of solutions of 186/EUM shower (red asterisks). The radiant of 186/00 shower is located near the star ε-Ursae-Majoris. The radiant of 186/01 is located in the constellation Draco close to the star ι-Draconis.
In the text

	Fig. 22 Radiants of solutions of 189/DMC shower (red asterisks). The radiant of 189/00 shower is located in the constellation Cancer near the star μ1-Cancri. The radiant of 189/01 is located in the Gemini constellation close to the star 52-Geminorum.
In the text

	Fig. 23 Radiants of solutions of 253/CMI shower (red asterisks). The radiant of 253/00 shower is located in the constellation Gemini, the radiant of 253/03 is located in the constellation Cancer.
In the text

	Fig. 24 Radiants of solutions of 327/BEQ shower (red asterisks). The radiant of 327/00 shower is located in the constellation Equuleus, and the radiant of 327/01 is located in the constellation Aquila.
In the text

Fig. 25 Distributions of e versus λS and 1 / Q versus inc (inverse of the distance of the aphelion versus the inclination of the orbit), 358 members of the 372/04 stream (green), and two points corresponding to the average values of the 372/04 (black) and 372/00 (red) solution. The mean values of the eccentricities of the two solutions are definitely different from each other. In the figure on the right, solution 372/00 belongs to the area to which known comets belong. Solution 372/00 is located in an area where known comets do not exist.

In the text