Oxygen line in fireball spectra and its application to satellite observations

0568797 - ASÚ 2023 RIV FR eng J - Článek v odborném periodiku
Vojáček, Vlastimil - Borovička, Jiří - Spurný, Pavel
Oxygen line in fireball spectra and its application to satellite observations.
Astronomy & Astrophysics. Roč. 668, Decedmber (2022), č. článku A102. ISSN 0004-6361. E-ISSN 1432-0746
Grant CEP: GA ČR(CZ) GX19-26232X
Grant ostatní: AV ČR(CZ) Akademická prémie - Praemium Academiae
Institucionální podpora: RVO:67985815
Klíčová slova: meteorites * meteors * meteoroids
Obor OECD: Astronomy (including astrophysics,space science)
Impakt faktor: 6.5, rok: 2022
Způsob publikování: Open access

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. 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.
Trvalý link: https://hdl.handle.net/11104/0340061