Unsolved Problems for Main-Sequence Variable Stars Revealed by the NASA Kepler Data (Abstract)

Volume 44 number 2 (2016)

Joyce Ann Guzik

432 Pruitt Avenue, White Rock, NM 87544; jguzik@mindspring.com

Abstract

(Abstract only) The NASA Kepler spacecraft’s long time-series photometric data have enabled interesting studies of g Doradus, d Scuti, slowly-pulsating B, and b Cephei variable stars by revealing many new variables and characterizing frequencies and amplitudes to high precision. These stars pulsate in multiple nonradial modes, with periods of hours to days.We will discuss some questions that the Kepler data have raised and are helping to solve, including: Why have so many “hybrid” g Dor/d Sct variables been discovered? Why are there apparently “constant” non-pulsating stars within the pulsation instability regions? What are the causes of amplitude variations that occur over relatively short timescales? Can we find patterns in the frequencies and amplitude spectra that will help with mode identification and facilitate asteroseismology? Are large increases in the opacities used for stellar models needed to explain the B-type pulsators and to solve the "solar abundance problem"?