Abstract

YOLDAş, E.  and  DAL, H. A.. A Pulsating Flare Star in the New Planetary System: KOI-258. Rev. mex. astron. astrofis [online]. 2021, vol.57, n.1, pp.39-55.  Epub Sep 30, 2021. ISSN 0185-1101.  https://doi.org/10.22201/ia.01851101p.2021.57.01.02.

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 are activity.

Keywords : planetary systems.