Seismological Studies of Pulsating DA White Dwarfs Observed with the Kepler Space Telescope and K2 Campaigns 1-8

Abstract

All single stars that are born with masses up to 8.5 - 10 $M_{\odot }$ will end their lives as a white dwarf (WD) star. In this evolutionary stage, WDs enter the cooling sequence, where the stars radiate away their thermal energy, and are basically cooling. As these stars cool, they reach temperatures and conditions that cause the stars to pulsate. Using differential photometry to produce light curves, we can determine the observed periods of pulsation from the WD. We used the White Dwarf Evolution Code (WDEC) to calculate a grid of over one million models with various temperature, stellar mass and mass of helium and hydrogen layers, and calculated their theoretical pulsation periods. In this paper, we describe our approach to WD asteroseismology using WDEC models and we present seismological studies for 29 observed DAVs in the Kepler and K2 datasets, 25 of which have never been analyzed using these observations, and 19 of which have never been seismically analyzed in any capacity before. Learning about the internal structure of WDs place important constraints on the WD cooling sequence and our overall understanding of stellar evolution for low mass stars.

arXiv comment22 pages, 9 Tables and 12 Figures, ApJ accepted

References in corpus (19)

• Evolutionary and pulsational properties of white dwarf stars
• Pulsating White Dwarf Stars and Precision Asteroseismology
• The cooling of CO white dwarfs: influence of the internal chemical distribution
• Pulsating white dwarfs: new insights
• White Dwarf Rotation as a Function of Mass and a Dichotomy of Mode Linewidths: Kepler Observations of 27 Pulsating DA White Dwarfs Through K2 Campaign 8
• Toward ensemble asteroseismology of ZZ Ceti stars with fully evolutionary models
• Measuring ^{12}C(&alpha,&gamma)^{16}O from White Dwarf Asteroseismology
• Asteroseismological study of massive ZZ Ceti stars with fully evolutionary models
• Seismological studies of ZZ Ceti stars. I. The model grid and the application to individual stars
• Fine Grid Asteroseismology of R548 and G117-B15A
• Mode identification of Pulsating White Dwarfs using the HST
• Asteroseismology of ZZ Ceti stars with fully evolutionary white dwarf models: I. The impact of the uncertainties from prior evolution on the period spectrum
• Towards a pure ZZ Ceti instability strip
• Discovery of 74 new bright ZZ Ceti stars in the first three years of TESS
• WDEC - A code for modeling white dwarf structure and pulsations
• Probing the structure of Kepler ZZ Ceti stars with full evolutionary models-based asteroseismology
• The search for ZZ Ceti stars in the original Kepler mission
• A puzzling periodicity in the pulsating DA white dwarf G 117-B15A
• New DA white dwarf models for asteroseismology of ZZ Ceti stars

Cited by in corpus (4)

• A systematic study of the connection between white dwarf period spectra and model structure
• A comparison of best fits obtained in white dwarf asteroseismology using the WDEC and the LPCODE
• Constraints from parallaxes and average period spacings in the asteroseismic study of 8 DAVs
• Seismic test of the mass-radius relationship of hydrogen-atmospheric white dwarf stars