Variability of newly identified B-type stars observed by Kepler

TL;DR

This study analyzes the pulsational variability of newly identified B-type stars observed by Kepler, revealing high-order g modes, potential period spacings, and comparing observations with theoretical pulsation models.

Contribution

It provides the first detailed frequency analysis of newly identified Kepler B-type stars, highlighting pulsation patterns and their relation to stellar models.

Findings

All stars show pulsational variability with high-order g modes.

Detected possible period spacings related to asymptotic pulsation modes.

Comparison with nonadiabatic models suggests mode instability and rotational effects.

Abstract

Recent re-determination of stellar atmospheric parameters for a sample of stars observed during the {\it Kepler} mission allowed to enlarge the number of {\it Kepler} B-type stars. We present the detailed frequency analysis for all these objects. All stars exhibit pulsational variability with maximum amplitudes at frequencies corresponding to high-order g modes. Peaks that could be identified with low-order p/g modes are also extracted for a few stars. We identified some patters in the oscillation spectra that can be associated with the period spacings that can result from the asymptotic nature of the detected pulsational modes. We also tentatively confront the observed oscillation characteristics with predictions from linear nonadiabatic computations of stellar pulsations. For high-order g modes the traditional approximation was employed to include the effects of rotation on the frequency values and mode instability.