A study of Pulsation & Rotation in a sample of A-K type stars in the Kepler field

Abstract

We present the results of time-series photometric analysis of 15106 A-K type stars observed by the Kepler space mission. We identified 513 new rotational variables and measured their starspot rotation periods as a function of spectral type and discuss the distribution of their amplitudes. We examined the well-established period-colour relationship that applies to stars of spectral types F5-K for all of these rotational variables and, interestingly, found that a similar period-colour relationship appears to extend to stars of spectral types A7 to early-F too. This result is not consistent with the very foundation of the period-colour relationship. We have characterized 350 new non-radial pulsating variables such as A- and F-type candidate $\delta$ Scuti, $\gamma$ Doradus and hybrid stars, which increases the known candidate non-radial pulsators in the Kepler field significantly, by $\sim$20\%. The relationship between two recently constructed observables, $Energy$ and $Efficiency$, was also studied for the large sample of non-radial pulsators, which shows that the distribution in the logarithm of $Energy$ ($\log(En)$) can be used as a potential tool to distinguish between the non-radial pulsators, to some extent. Through visual inspection of the light curves and their corresponding frequency spectra, we found 23 new candidate red giant solar-like oscillators not previously reported in the literature. The basic physical parameters such as masses, radii and luminosities of these solar-like oscillators were also derived using asteroseismic relations.