The Classificiation of Kepler B star Variables

TL;DR

This study analyzes Kepler data of 252 B-star candidates to classify their variability types, significantly expanding the known sample of variable B stars and identifying interesting features like frequency groupings.

Contribution

It provides a detailed classification of B-star variability in Kepler data, increasing the known numbers of various variable star types and identifying pulsating white dwarf candidates.

Findings

Increased the number of identified $eta$ Cep stars to 10

Expanded the sample of slowly pulsating B stars to 54

Discovered 11 pulsating white dwarf candidates with frequency groupings

Abstract

The light curves of 252 B-star candidates in the Kepler data base are analyzed in a similar fashion to that done by Balona et al. (2011) to further characterize B star variability, increase the sample of variable B stars for future study, and to identify stars whose power spectra include particularly interesting features such as frequency groupings. Stars are classified as either constant light emitters, $\beta$ Cep stars, slowly pulsating B stars, hybrid pulsators, binaries or stars whose light curves are dominated by rotation (Bin/Rot), hot subdwarfs, or white dwarfs. One-hundred stars in our sample were found to be either light contants or to be variable at a level of less than 0.02 mmag. We increase the number of candidate B-star variables found in the Kepler data base by Balona et al. (2011) in the following fashion: $\beta$ Cep stars from 0 to 10, slowly pulsating B stars from 8 to 54, hybrid pulsators from 7 to 21, and Bin/Rot stars from 23 to 82. For comparison purposes, approximately 51 SPBs and 6 hybrids had been known prior to 2007. The number of $\beta$ Cep stars known prior to 2004 was 93. A secondary result of this study is the identification of an additional 11 pulsating white dwarf candidates, four of which possess frequency groupings.