Open AccessA PULSATING FLARE STAR IN THE NEW PLANETARY SYSTEM: KOI-258
Author(s) -
Ezgi Yoldaş,
H. A. Dal
Publication year - 2021
Publication title -
revista mexicana de astronomía y astrofísica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.123
H-Index - 34
ISSN - 0185-1101
DOI - 10.22201/ia.01851101p.2021.57.01.02
Subject(s) - physics , planet , astrophysics , star (game theory) , flare , flare star , line (geometry) , variation (astronomy) , amplitude , plateau (mathematics) , radial velocity , astronomy , stars , k type main sequence star , t tauri star , optics , mathematical analysis , geometry , mathematics
We present findings about the nature of KOI-258. Its temperature was found to be 6500 ± 200 K from its spectrum, which also indicates that the target is a single main sequence star despite the existence of a radial velocity variation with a small amplitude. Ca II H, K lines indicate the existence of magnetic activity, though there is no remarkable excess or variation in the Hα line. We found 51 flares with a frequency of 0.00186 h−1, whose plateau value is 0.659 s. Apart from the flares, we found 420 frequencies due to solar-like oscillations at out-of-eclipses. Removing these 420 frequencies, we demonstrated three different transits caused by three exo-planets. Their radii were found to be 2.33 R_⊕ for the first planet, 0.53 R_⊕ for the second one, and 1.15 R_⊕ for the third planet. Consequently, KOI-258 is an oscillating, single, main sequence star, with in a planetary system and remarkable flare activity.