Issue |
A&A
Volume 668, December 2022
|
|
---|---|---|
Article Number | A102 | |
Number of page(s) | 17 | |
Section | Planets and planetary systems | |
DOI | https://doi.org/10.1051/0004-6361/202244217 | |
Published online | 09 December 2022 |
Oxygen line in fireball spectra and its application to satellite observations
Astronomical Institute of the Czech Academy of Sciences,
Fričova 298,
251 65
Ondřejov, Czech Republic
e-mail: vojacek@asu.cas.cz
Received:
8
June
2022
Accepted:
10
October
2022
Aims. Lightning mapper sensors on board weather satellites can be successfully used to observe fireballs. These sensors use a very narrow spectral band at 777 nm, which is only a small fraction of the total fireball radiation. In this spectral band, the oxygen O I-1 triplet is dominant for fast meteors and the Planck continuum can prevail in slow meteors. It is possible to estimate the meteor brightness in the visible spectral range from this narrowband radiation, but it is vital to first study the dependence of this radiation on the meteor velocity.
Methods. We used observations from the well-established European Fireball Network with newly developed digital spectral cameras that allowed us to study the oxygen triplet in meteor spectra and its relation to the meteor velocity and altitude. In addition, we studied strong magnesium and sodium lines.
Results. We developed a method for calibration of fireball observation reported by Geostationary Lightning Mapper (GLM) sensors on board the Geostationary Operational Environmental Satellite (GOES) weather satellites. We confirm that in slow meteors, the radiation of the Planck continuum dominates, but for faster meteors, a correction on velocity is needed. We observe that the altitude where the oxygen line was recorded can also affect the radiation at 777 nm. In addition, determining whether or not the meteor showed a bright flare could also lead to a similar effect. Thus, the meteor brightness estimate may be impacted by these characteristics. We derived simple corrections on the altitude and on the meteor brightness that helped to improve the overall precision of the magnitude estimate of our sample. This allowed us to estimate the magnitude of meteors observed by GLM with an accuracy of ≈1 in magnitude. The Na/Mg line intensity ratio was found to be constant for velocities above 25 km s−1 and increasing toward lower velocities.
Key words: meteorites / meteors / meteoroids / planets and satellites: atmospheres / techniques: spectroscopic
© V. Vojáček et al. 2022
Open 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.
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.