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

## TL;DR

This study analyzes Kepler data of 15,106 A-K stars, discovering new rotational and pulsating variables, examining period-colour relationships, and identifying candidate solar-like oscillators, thereby expanding understanding of stellar variability.

## Contribution

It presents the identification of new rotational and non-radial pulsating stars, extending period-colour relations, and discovering candidate solar-like oscillators in the Kepler field.

## Key findings

- Identified 513 new rotational variables with starspot periods.
- Discovered that the period-colour relationship extends to A7-F stars.
- Found 23 candidate red giant solar-like oscillators.

## 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.