EDP Sciences logo
Subscriber Authentication Point
Search
Menu
Home All issues Volume 664 (August 2022) A&A, 664 (2022) A96 Full HTML
Open Access
Issue
A&A
Volume 664, August 2022
Article Number A96
Number of page(s) 15
Section Catalogs and data
DOI https://doi.org/10.1051/0004-6361/202243723
Published online 15 August 2022

© P. Zasche et al. 2022

Licence Creative CommonsOpen Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

This article is published in open access under the Subscribe-to-Open model. Subscribe to A&A to support open access publication.

1 Introduction

More than 200 yr ago, it was proposed that the brightness changes in Algol are caused by an obscuring body and its orbit around the main star (Goodricke 1783). This was the moment when eclipsing binary research was born. However, two centuries passed before it became clear that eclipsing binaries could provide absolutely unique insight into basic stellar properties, such as masses, radii, and luminosities. Their role in current astrophysical research is undisputable (see e.g. Southworth 2012), and nowadays, in the era of huge photometric surveys and projects, their number is increasing rapidly, meaning that they can be used to calibrate existing stellar models of evolution.

In addition, thanks to large surveys, significantly reduced scatter, and a tremendously increasing number of known systems, we are also able to discover and study much more complicated objects. For example, the huge survey Optical Gravitational Lensing Experiment (OGLE; Udalski et al. 1992) was used to identify about a thousand new candidate triple stars by studying period changes using the so-called eclipse timing variation (ETV) method; see Hajdu et al. (2019).

Moreover, a relatively new group of objects, nowadays known as doubly eclipsing systems, are also mostly being discovered thanks to large photometric surveys like OGLE, Kepler, Corot, and TESS (see e.g. Soszyński et al. 2016; Lehmann et al. 2012; Hajdu et al. 2017; and Kostov et al. 2021). These objects show two distinct eclipsing periods coming from one point source on the sky. The study of such stars should bring us fresh insight into stellar formation mechanisms (see e.g. Tokovinin 2021). Nevertheless, if both these eclipsing binaries are really bound to each other and share a common orbit around their barycenter, both should also share the same distance, age, and metallicity. This is an important aspect, which should be tested when analysing a particular system, and can be used to set tight constraints on our model.

Our main motivation for discovering and studying such systems is the fact that they represent ideal astrophysical laboratories. They allow us to study celestial mechanics in ‘real time’, the dynamical influence between the inner and outer orbits, Kozai cycles, the dynamical evolution of the orbits, such as precession and inclination changes, and so on. Moreover, with enough such 2+2 quadruples with known orbits, one can study their origin, and subsequent evolution. We aim to decipher whether they are products of disc fragmentation, or N-body dynamics, and to investigate the mean motion resonances of both inner pairs. Many questions remain to be answered, and larger and more robust samples will bring useful information.

2 The Selection Process

The first doubly eclipsing system confirmed showing two eclipsing periods was V0994 Her (Lee et al. 2008). Nowadays the group comprises about 160 doubly eclipsing systems with both periods being known. However, some of them could still be blends of two close-by components not connected gravitation-ally, and the mutual orbit is only known for a few of these latter. This is a serious problem, especially in dense star fields: one cannot definitively prove that the signal of two periods comes to our telescope from one point source on the sky. The large survey OGLE discovered several dozen doubly eclipsing systems in dense Large and Small Magellanic Clouds (LMC and SMC) fields, and in closer Galactic bulge fields (Graczyk et al. 2011; Pawlak et al. 2013; Soszyński et al. 2016).

In addition, quite recently it was discovered that quite a significant fraction of new doubly eclipsing binaries are found in already known and bright eclipsing binaries. The problem is usually that these additional eclipses were missed because of their small amplitude (compared with the dominant pair, as in V0482 Per; Torres et al. 2017), or because these stars are sometimes easily too bright for modern telescopes (as in BU CMi; Jayaraman et al. 2021). Possibly the most remarkable example is the system BG Ind, which was studied in detail with ground-based photometry (Rozyczka et al. 2011) having not previously noticed anything suspicious. However, TESS data revealed that BG Ind is the nearest doubly eclipsing system (Borkovits et al. 2021), and it was being missed simply due to the overly shallow photometric amplitude of pair B. Sometimes only small parts of the light curves near eclipses are observed, and the rest is monitored only very rarely, which leads to non-detection of the additional eclipses (like for V0498 Cyg; see Southworth 2022).

Taking into account all these aspects and limitations, we decided to use the extremely precise and freely available database of the TESS satellite (Ricker et al. 2015), and to scan as many potential systems as possible. Nowadays, probably the most complete database of information on variable stars is that one running under The American Association of Variable Star Observers (AAVSO), named The International Variable Star Index (VSX; Watson et al. 2006), comprising about a million eclipsing binaries with known periods to date. Our method was quite simple: scanning all known eclipsing binaries found in the VSX with known periods, and trying to identify some additional eclipses in the TESS data. Only those with given magnitudes brighter than 15 mag were considered. We checked all Algol-type (EA) stars from the VSX for additional eclipses. This group of stars comprises the huge majority of the systems in our sample. Among the others we identified only a handful of other stars with β Lyrae (EB) or W UMa (EW) classification with periods longer than 0.5 days. In addition, we plotted and checked all systems from the CzeV catalogue (Skarka et al. 2017).

For some of the systems, the additional eclipses were seen directly when plotting TESS fluxes versus time, but for others we needed first to subtract the dominant eclipsing binary shape and later to search for additional eclipses on the residuals. Plotting the TESS photometric data in the phased light curve with a particular period is a straightforward task with the available program named lightkurve (Lightkurve Collaboration 2018). A technique relying on detection with the naked eye was found to be the most effective for finding these additional eclipses in the data. The human eye is a very sensitive tool when looking for additional patterns in the already very periodic signal, such as those formed by ordinary eclipsing binaries. We are aware of its limitations, as well as of the limitation of the large TESS pixels (see below for a more detailed discussion).

3 Method

We checked about 70 000 stars in total; we downloaded their data, plotted their light curves, and checked for additional eclipses. Many suspected cases were studied in more detail, in an attempt to definitively confirm whether the strange behaviour of the TESS data is due to improper reduction, or real changes in brightness. The results of our in-depth scanning of the VSX and TESS data are summarised in the following section.

Our goal was not analyse these systems in detail, but only to present a catalogue of candidate systems; that is, stars for which one simple period was not able to describe all the eclipses identified in the TESS data. In total, 141 such stars were found, among them 116 doubly eclipsing ones, and 25 candidates of triply eclipsing triple stars. Several other systems were also found, as suspected, but their nature is still rather questionable (most often the contact W UMa-type shape and short periodic pulsation patterns are too similar).

Our method of disentangling the complete photometry into two separate light curves of both pairs is rather straightforward. We used the program named Silicups (version 2.991), which uses a phenomenological model for the phased light curve. Such a preliminary light curve fit can be subtracted and one can easily see whether some additional eclipses are also visible on the residual light curve. Where this was the case, we used a period-searching algorithm to detect the secondary period PB (using a PDM method).

As one can see from our Fig. 1, our detected candidate doubly eclipsing systems nicely fill the incomplete statistics. Up to now, most of the detected doubly eclipsing systems were found in the OGLE fields, in both the LMC and SMC, and the Galactic disc and bulge. However, these OGLE data comprise somewhat biased photometric data (e.g. observing strategy over the years, data cadency of observations, etc.), and therefore also the detected doubly eclipsing systems are definitely slightly different from those in the TESS data (almost complete detection of binaries with P < 27 days). There are two particularly important aspects here. At first, the cadence of the OGLE data is typically only one observation per night, but the overall time-span (on the LMC and SMC) is more than 10 yr. On the other hand, the TESS data provide continuous undisturbed photometry over 27 days. The second important aspect is the typical scatter, or error, of individual data points. OGLE provides data with about 0.01 mag scatter, while the scatter for TESS data is an order of magnitude lower. Therefore, the level of eclipse depth detectable in both surveys should also be rather different and many of the systems detected by our method here are definitely not visible in the OGLE data. Finally, the angular resolution of the TESS and the OGLE data is also very different.

On the other hand, what Fig. 1 also shows us is the fact that our sample of newly detected systems (marked in blue) show a much higher tendency to be closer to the Galactic disc than the rest of the other bright TESS targets. Qualitatively, the stars closer than 10° from the disc comprise about three-quarters of our sample, but contain only about one-quarter of the TESS stars. It is therefore questionable as to whether the number of doubly eclipsing binaries is higher in the Galactic disc (due to higher star density, and perhaps therefore higher probability of blending). However, we prefer an alternative explanation, namely the fact that all the stars in our sample come from the known eclipsing systems, which are mostly being discovered in large photometric surveys detecting most of their variables preferably closer to the Galactic disc.

Concerning the two periods, the more prominent one is typically that of pair A (which usually has deeper eclipses), but some exceptions exist. Our primary period of pair A is always that given in the VSX catalogue, and the period of pair B is the new derived one.

One might ask how we deal with the blending problem within the large TESS pixels. In the huge majority of the systems, we were also able to identify both sets of eclipses from older ground-based photometry with better angular resolution. These were namely the ASASsn (Kochanek et al. 2017; Shappee et al. 2014), ZTF (Masci et al. 2019), and SWASP (Pollacco et al. 2006) data. The ZTF survey in particular was a very useful source of photometry, with its high angular resolution helping us to rule out the blending of the two close-by sources. Several blends of two close stars were also proven as a by-product of our analysis (like V0432 CMa, ASASSN-V J020003.56+452605.2, and ASASSN-V J123052.13-475634.5).

thumbnail Fig. 1

Sky distribution of our candidate stars (blue) together with all known doubly eclipsing systems (red), plotted together with other stars from TESS (only 50 000 brightest stars).
thumbnail Fig. 2

Distribution of individual eclipsing binary types from our detected sample. As one can see, the vast majority are the EA+EA systems, which are most easily discovered in the TESS data.

4 Results

In total, we detected 116 systems as 2+2 quadruple doubly eclipsing candidates. The huge majority of these should be characterised as EA + EA (see Table A.1, and Fig. 2). This phe-nomenological classification only tells us that our method is able to discover such systems more easily, simply because the two periodic curves are more easily disentangled into the two periods and their shape is definitely ‘eclipse-like’. All of the disentangled light curves of both pairs are plotted in Figs. A.1–A.8. For all of the systems, we use its original name within the VSX database and give also the TIC number for identification and coordinates in Table A.1.

Figure 3 shows for illustration how difficult it can be to detect the additional eclipses of pair B from the ground when only poorly sampled data are available. A good example is the eccentric system V0384 Cen, which has been observed many times in the past, with nobody noticing the distorted shape of the minima and that these deviations are periodic, coming from the unseen additional pair. This is a typical example of a bright system observed in the past, where a second pair has an order of magnitude smaller photometric amplitude. Unfortunately, the observers usually only observe the eclipses, and sometimes even their bottom parts only. In such cases, the detection of pair B is often quite difficult. This hightlights the great advantage of the continuous TESS data, where targets are observed with superb precision for many days in a row.

The systems classified as triply eclipsing triples (see e.g. quite recent study by Borkovits et al. 2022) were easily distinguished from the doubly eclipsing quadruples because of the shapes of the additional eclipses (a ‘double peak’) and also their uniqueness (i.e. long orbits, long periods, only rarely observed in the TESS data). These systems are given below in Table 1. The other ground-based photometric surveys were usually also used for detecting the outer periods of the third body. This was partly successful for several systems (because of their large depths and the long-lasting monitoring in these surveys) and we also give their outer periods in the last column of Table 1. Their light curves, which in addition to the “ordinary” eclipses also show other eclipses are given in Fig. A.9.

Probably the most interesting system seems to be ASASSN-V J101237.44-594344.8, which shows large variations of ETV for the inner pair A and also exhibits eclipse-depth variations (both in the TESS data as well as in the older ground-based photometry). In the following list, we briefly mention those systems that were found to be interesting in some aspect resulting from our analysis. Some of them were found to be located very close to the mean motion resonance configuration, as already proposed in our previous paper (Zasche et al. 2019), and studied also theoretically by Tremaine (2020).

  • ASASSN-V J004727.28+644904.9 : very eccentric pair B (secondary eclipse in phase 0.705).

  • ASASSN-V J020306.68+624315.4 : very eccentric pair B (secondary eclipse in phase 0.26).

  • ASASSN-V J024221.82+625403.6 : almost exact 2:1 resonance (only 0.2% off).

  • V1018 Cas: eccentric pair A, close to 4:3 resonance.

  • V0417 Aur : change of classification here. Former classification as pulsating-eclipsing oEA is now more probably an EA + EW system.

  • ASASSN-V J064048.28-224659.0 : eclipses of pair B are visible in TESS data only in 2020, and are missing in 2019 and 2018 (orbital precession?).

  • ASASSN-V J071131.63-153341.3 : eccentric pair A, close to 2:3 resonance.

  • ASASSN-V J072304.90-110043.5 : eccentric pair B.

  • V0674 Pup : eccentric pair B.

  • WISE J075848.7-374315 : possible period changes.

  • CPD-34 3002 : slightly eccentric pair A.

  • ASASSN-V J091951.17-593306.9 : eccentric system (secondary eclipse in phase 0.44).

  • ASASSN-V J092031.34-542438.1 : eccentric pair B.

  • WISE J100820.0-731554 : period changes; eccentric pair B, close double star according to Gaia (probably bound – similar π, and PM).

  • ASAS J103449-6013.1 : double star, two components separated by about 2.3″, eccentric pair A.

  • ASASSN-V J105824.33-611347.6: very fast apsidal motion or other ETV phenomena for pair A, eccentric also pair B.

  • ASAS J113426-6320.0 : slightly eccentric pair A, very eccentric pair B (second minimum in phase 0.72).

  • V0384 Cen : well-known eccentric binary A, see Fig. 3.

  • KELT KS38C016096 : asymmetric light curve shape for pair A (spots?).

  • ASASSN-V J125427.31-653437.7 : possible period changes.

  • ASASSN-V J155157.55-430547.7 : eccentric pair B.

  • ASASSN-V J173344.14-363037.8 : possible period changes, eccentric B.

  • ASASSN-V J184212.96-775807.0 : possible period changes.

  • V1356 Cyg : eccentric pair B.

  • Brh V154 : close to resonance 7:2 (only 0.1% off).

  • ASASSN-V J201545.10+373555.2 : eccentric pair A.

  • ZTF J205229.71+473345.9 : almost exactly in 5:3 resonance (only 0.01% off).

  • ASASSN-V J222721.05+564425.3 : both pairs A and B are eccentric.

  • ZTF J224132.79+582517.4 : eccentric pair B, longest period in our sample.

  • ASASSN-V J233336.79+615012.0 : eccentric pair A.

One system that definitely merits our attention is V0871 Cen (= HD 101205 = TIC 319936710, see Fig. 4). This is the brightest system in our sample of stars, is a member of the cluster IC 2944, and is very often studied both photometrically and spectroscopically (see e.g. Mayer et al. 1992; Otero 2007; Sana et al. 2011). A photometric period of about 2.09 days has been detected for this star with its Algol-like eclipsing light curve, together with a spectroscopic period of 2.8 days. Moreover, the whole system has been found to be much more complicated, containing three other close visual companions in addition to the inner brightest companion A, namely B, C, and D (with separations of 0.36″, 1.7″, and 9.6″). However, until now, it was not known which of the inner ABC components contain the eclipsing binary and which is the spectroscopic pair. Now, using the extremely precise TESS data we are able to detect both 2.09 d and 2.8 d period signals in the photometric data, and can also detect the possible mutual eclipse on their orbit around a common barycenter. Due to the fact that the mutual movement of the A-B pair is only very slow, namely of the order of thousands of years (Zasche et al. 2009), and hence the probability of the mutual eclipse on such an orbit right now in the TESS epoch is very improbable, we have to conclude that the architecture of the whole system is as follows. The most inner two pairs are the 2.8 d and 2.09 d binaries (we name these Aa-Ab), accompanied by a more distant component B with its only poorly constrained orbit by Zasche et al. (2009). The much more distant C and D components are probably bound (due to their similar proper motion), but only very weakly. The whole system is likely septuple. Its 2.8 d photometric variation was not noticed earlier because of is its much lower amplitude compared to the dominant pair A.

Finally, we also found the star ASASSN-V J124203.23-644513.2 to be extremely interesting. In addition to the two eclipsing periods of pairs A and B (periods 2.0725, and 1.4123 days), this system shows an eclipse observed by TESS (see Fig. 5). However, its shape is ‘double-peaked’, as in triply eclipsing triples, and its depth is similar to that of pair A, indicating that pair A is being eclipsed at that time. Three probable explanations emerge: (1) a quadruple 2+2 doubly eclipsing system, which is also perfectly coplanar, meaning that even this mutual orbit is eclipsing; (2) a doubly eclipsing system with one additional component (architecture 2+2+1) causing this eclipse; or (3) a blend of unconnected stars, that is, two systems: a triple and a binary.

thumbnail Fig. 3

Sample light curve of V0384 Cen from the TESS data. Left panel: data from sector 38 with eclipses of both pairs in time. Right panel: only the phased part of the curve near the primary eclipses of pair A, showing how pair B distorts the shape of the eclipse in different sectors of the data. Moreover, the depth of the eclipse is also obviously different in different sectors. This can be caused by two different phenomena. Firstly, the apsidal motion and change of omega on the eccentric orbit, and secondly an artifact from the TESS reduction causing different third light values in the different sectors of data.
thumbnail Fig. 4

System V0871 Cen with its complete light curve, showing two additional prominent periods PAa and PAb (eclipses of both pairs denoted by short abscissae of blue for the primary, and red for the secondary eclipses, with longer solid ones for pair Aa, and shorter dash-dotted for pair Ab) and an additional eclipse, which we believe is the outer eclipse of their mutual orbit Aa-Ab around a common barycenter.
Table 1

Triply eclipsing triple candidates.

thumbnail Fig. 5

System named ASASSN-V J124203.23-644513.2 showing, in addition to both inner eclipsing periods, an eclipse with quite a complicated structure, possibly indicating a coplanar 2+2 system with its outer mutual eclipses. These data are ‘pre-whitened’ to clearly see this additional eclipse, i.e. both inner eclipsing curves were subtracted.

5 Conclusions

We carried out an analysis of all EA-type binaries from the VSX database (with <15 mag) in an attempt to identify additional eclipses in the TESS data. Our compilation of 141 systems is so far the most extensive among other similar studies. The database we present should be useful to observers and keen astronomers for detailed follow-up monitoring of these interesting targets. For this reason, we give the ephemerides for both eclipsing pairs, but also their eclipse depths. These are crucial parameters for prospective future observations.

Such monitoring is potentially very important because of the chance of detecting the ETV for both pairs, which could be used to prove their quadruple nature. According to our previous findings (Zasche et al. 2019), we believe that most of these candidate stars will be confirmed as quadruples thanks to intensive ground-based observations in the upcoming years. Such long-lasting monitoring will be our main task for the future seasons. We have already begun to collect data with our group of keen astronomers using their relatively modest equipment, which is nevertheless quite adequate for such a task. We find a combination of two pieces of software, namely SIPS (for reduction of the CCD frames) and SILICUPS (for plotting and subtracting the individual light curve shapes), to be particularly suitable for reducing and analysing such complicated systems.

Acknowledgements

We would like to thank Dr. Dariusz Graczyk as a referee for his valuable suggestions and remarks improving the overall quality of the manuscript. We do thank the NSVS, ZTF, ASAS-SN, SWASP, and TESS teams for making all of the observations easily public available. The research of P.Z. was supported by the project Progress Q47 PHYSICS of the Charles University in Prague. This work is supported by MEYS (Czech Republic) under the project MEYS LTT17006. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. This research made use of Lightkurve, a Python package for TESS data analysis (Lightkurve Collaboration 2018). This research has made use of the SIMBAD and VIZIER databases, operated at CDS, Strasbourg, France and of NASA Astrophysics Data System Bibliographic Services.

Appendix A Additional Material

thumbnail Fig. A.1

Light curves of both pairs as disentangled from the original TESS photometry. Plotted in ascending order of Right Ascension.
thumbnail Fig. A.2

Light curves of both pairs as disentangled from the original TESS photometry, continuation.
thumbnail Fig. A.3

Light curves of both pairs as disentangled from the original TESS photometry, continuation.
thumbnail Fig. A.4

Light curves of both pairs as disentangled from the original TESS photometry, continuation.
thumbnail Fig. A.5

Light curves of both pairs as disentangled from the original TESS photometry, continuation.
thumbnail Fig. A.6

Light curves of both pairs as disentangled from the original TESS photometry, continuation.
thumbnail Fig. A.7

Light curves of both pairs as disentangled from the original TESS photometry, continuation.
thumbnail Fig. A.8

Light curves of both pairs as disentangled from the original TESS photometry, continuation.
thumbnail Fig. A.9

Light curves of triply eclipsing triples. The eclipses of the inner pair are denoted by short abscissae in blue for primary, and red for secondary eclipses. Extra eclipses are clearly visible.
Table A.1

Doubly eclipsing candidates.

Note Added in Proof

Following submission of the present manuscript, an independent paper dealing with the same topic was published by Kostov et al. (2022). The authors present a group of 97 doubly eclipsing systems found in the TESS database, but identified with a different method (scanning all stars instead of only known eclipsing binaries, as we did). Due to this difference in approach, there is relatively little overlap in the systems we find; in total 18 systems, which are marked with an asterisk in Table A.1.

References

  1. Borkovits, T., Rappaport, S. A., Maxted, P. F. L., et al. 2021, MNRAS, 503, 3759 [NASA ADS] [CrossRef] [Google Scholar]
  2. Borkovits, T., Mitnyan, T., Rappaport, S. A., et al. 2022, MNRAS, 510, 1352 [Google Scholar]
  3. Goodricke, J. 1783, Phil. Trans. R. Soc. London, Ser. I, 73, 474 [Google Scholar]
  4. Graczyk, D., Soszyński, I., Poleski, R., et al. 2011, Acta Astron., 61, 103 [Google Scholar]
  5. Hajdu, T., Borkovits, T., Forgács-Dajka, E., et al. 2017, MNRAS, 471, 1230 [NASA ADS] [CrossRef] [Google Scholar]
  6. Hajdu, T., Borkovits, T., Forgács-Dajka, E., et al. 2019, MNRAS, 485, 2562 [NASA ADS] [CrossRef] [Google Scholar]
  7. Jayaraman, R., Rappaport, S., Borkovits, T., et al. 2021, 10.5281/zenodo.5117858 [Google Scholar]
  8. Kochanek, C. S., Shappee, B. J., Stanek, K. Z., et al. 2017, PASP, 129, 104502 [Google Scholar]
  9. Kostov, V. B., Powell, B. P., Torres, G., et al. 2021, ApJ, 917, 93 [NASA ADS] [CrossRef] [Google Scholar]
  10. Kostov, V. B., Powell, B. P., Rappaport, S. A., et al. 2022, ApJS, 259, 66 [CrossRef] [Google Scholar]
  11. Lasker, B. M., Lattanzi, M. G., McLean, B. J., et al. 2008, AJ, 136, 735 [Google Scholar]
  12. Lee, C.-U., Kim, S.-L., Lee, J. W., et al. 2008, MNRAS, 389, 1630 [NASA ADS] [CrossRef] [Google Scholar]
  13. Lehmann, H., Zechmeister, M., Dreizler, S., et al. 2012, A&A, 541, A105 [NASA ADS] [CrossRef] [EDP Sciences] [Google Scholar]
  14. Lightkurve Collaboration (de Cardoso, J. V. M., et al.) 2018, Astrophysics Source Code Library [record ascl:1812.013] [Google Scholar]
  15. Masci, F. J., Laher, R. R., Rusholme, B., et al. 2019, PASP, 131, 018003 [Google Scholar]
  16. Masuda, K., Uehara, S., & Kawahara, H. 2015, ApJ, 806, L37 [NASA ADS] [CrossRef] [Google Scholar]
  17. Mayer, P., Lorenz, R., & Drechsel, H. 1992, Information Bull. Variab. Stars, 3765, 1 [Google Scholar]
  18. Otero, S. A. 2007, Open Eur. J. Variab. Stars, 0072, 1 [NASA ADS] [Google Scholar]
  19. Pawlak, M., Graczyk, D., Soszyński, I., et al. 2013, Acta Astron., 63, 323 [NASA ADS] [Google Scholar]
  20. Pollacco, D. L., Skillen, I., Collier Cameron, A., et al. 2006, PASP, 118, 1407 [NASA ADS] [CrossRef] [Google Scholar]
  21. Rappaport, S., Borkovits, T., Gagliano, R., et al., 2022, MNRAS, 513, 4341 [NASA ADS] [CrossRef] [Google Scholar]
  22. Ricker, G. R., Winn, J. N., Vanderspek, R., et al. 2015, JATIS, 1, 014003 [Google Scholar]
  23. Rozyczka, M., Kaluzny, J., Pych, W., et al. 2011, MNRAS, 414, 2479 [Google Scholar]
  24. Sana, H., James, G., & Gosset, E. 2011, MNRAS, 416, 817 [Google Scholar]
  25. Shappee, B. J., Prieto, J. L., Grupe, D., et al. 2014, ApJ, 788, 48 [Google Scholar]
  26. Skarka, M., Mašek, M., Brát, L., et al. 2017, OEJV, 185, 1 [NASA ADS] [Google Scholar]
  27. Soszyński, I., Pawlak, M., Pietrukowicz, P., et al. 2016, Acta Astron., 66, 405 [NASA ADS] [Google Scholar]
  28. Southworth, J. 2012, Orbital Couples: Pas de Deux in the Solar System and the Milky Way, 51 [Google Scholar]
  29. Southworth, J. 2022, The Observatory, accepted, ArXiv e-prints [arXiv:2201.02516] [Google Scholar]
  30. Tokovinin, A. 2021, Universe, 7, 352 [NASA ADS] [CrossRef] [Google Scholar]
  31. Torres, G., Sandberg Lacy, C. H., Fekel, F. C., et al. 2017, ApJ, 846, 115 [NASA ADS] [CrossRef] [Google Scholar]
  32. Tremaine, S. 2020, MNRAS, 493, 5583 [NASA ADS] [CrossRef] [Google Scholar]
  33. Udalski, A., Szymanski, M., Kaluzny, J., et al. 1992, Acta Astron., 42, 253 [NASA ADS] [Google Scholar]
  34. Watson, C. L., Henden, A. A., & Price, A. 2006, SASS, 25, 47 [NASA ADS] [Google Scholar]
  35. Zacharias, N., Finch, C. T., Girard, T. M., et al. 2013, AJ, 145, 44 [Google Scholar]
  36. Zasche, P., Wolf, M., Hartkopf, W. I., et al. 2009, AJ, 138, 664 [NASA ADS] [CrossRef] [Google Scholar]
  37. Zasche, P., Vokrouhlický, D., Wolf, M., et al. 2019, A&A, 630, A128 [NASA ADS] [CrossRef] [EDP Sciences] [Google Scholar]

All Tables

Table 1

Triply eclipsing triple candidates.

In the text
Table A.1

Doubly eclipsing candidates.

In the text

All Figures

thumbnail Fig. 1

Sky distribution of our candidate stars (blue) together with all known doubly eclipsing systems (red), plotted together with other stars from TESS (only 50 000 brightest stars).
In the text
thumbnail Fig. 2

Distribution of individual eclipsing binary types from our detected sample. As one can see, the vast majority are the EA+EA systems, which are most easily discovered in the TESS data.
In the text
thumbnail Fig. 3

Sample light curve of V0384 Cen from the TESS data. Left panel: data from sector 38 with eclipses of both pairs in time. Right panel: only the phased part of the curve near the primary eclipses of pair A, showing how pair B distorts the shape of the eclipse in different sectors of the data. Moreover, the depth of the eclipse is also obviously different in different sectors. This can be caused by two different phenomena. Firstly, the apsidal motion and change of omega on the eccentric orbit, and secondly an artifact from the TESS reduction causing different third light values in the different sectors of data.
In the text
thumbnail Fig. 4

System V0871 Cen with its complete light curve, showing two additional prominent periods PAa and PAb (eclipses of both pairs denoted by short abscissae of blue for the primary, and red for the secondary eclipses, with longer solid ones for pair Aa, and shorter dash-dotted for pair Ab) and an additional eclipse, which we believe is the outer eclipse of their mutual orbit Aa-Ab around a common barycenter.
In the text
thumbnail Fig. 5

System named ASASSN-V J124203.23-644513.2 showing, in addition to both inner eclipsing periods, an eclipse with quite a complicated structure, possibly indicating a coplanar 2+2 system with its outer mutual eclipses. These data are ‘pre-whitened’ to clearly see this additional eclipse, i.e. both inner eclipsing curves were subtracted.
In the text
thumbnail Fig. A.1

Light curves of both pairs as disentangled from the original TESS photometry. Plotted in ascending order of Right Ascension.
In the text
thumbnail Fig. A.2

Light curves of both pairs as disentangled from the original TESS photometry, continuation.
In the text
thumbnail Fig. A.3

Light curves of both pairs as disentangled from the original TESS photometry, continuation.
In the text
thumbnail Fig. A.4

Light curves of both pairs as disentangled from the original TESS photometry, continuation.
In the text
thumbnail Fig. A.5

Light curves of both pairs as disentangled from the original TESS photometry, continuation.
In the text
thumbnail Fig. A.6

Light curves of both pairs as disentangled from the original TESS photometry, continuation.
In the text
thumbnail Fig. A.7

Light curves of both pairs as disentangled from the original TESS photometry, continuation.
In the text
thumbnail Fig. A.8

Light curves of both pairs as disentangled from the original TESS photometry, continuation.
In the text
thumbnail Fig. A.9

Light curves of triply eclipsing triples. The eclipses of the inner pair are denoted by short abscissae in blue for primary, and red for secondary eclipses. Extra eclipses are clearly visible.
In the text

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.