New DA white dwarf models for asteroseismology of ZZ Ceti stars

Abstract

Asteroseismology is a powerful tool to infer the evolutionary status and chemical stratification of white dwarf (WD) stars, and to explore the physical processes that lead to their formation. This is particularly true for the variable H-rich atmosphere (DA) WDs, known as DAV or ZZ Ceti stars. We present a new grid of DA WD models that take into account the last advances in the modeling and input physics of both the progenitor and the WD stars, thus avoiding and improving several shortcomings present in the set of DA WD models employed in the asteroseismological analyses of ZZ Ceti stars we carried out in our previous works. These new models are derived from a self-consistent way with the changes in the internal chemical distribution that result from the mixing of all the core chemical components induced by mean molecular-weight inversions, from ${}^{22}$Ne diffusion, Coulomb sedimentation, and from residual nuclearburning. In addition, the expected nuclear-burning history and mixing events along the progenitor evolution are accounted for, in particular the occurrence of third dredge-up, which determines the properties of the core and envelope of post-AGB and white dwarf stars, as well as the WD initial-final mass relation. The range of H envelopes of our new ZZ star models extends from log(M_H/M_*)= -4 to -5, to log(M_H/M_*)= -13.5. This allows, for the first time, to consider seismological solutions for ZZ Ceti stars with extremely thin H envelopes. Our new H-burning post-AGB models predict chemical profiles of O and C near the stellar centre of ZZ Ceti stars substantially different from those we used in our previous works. We find that the pulsation periods of $g$ modes and the mode-trapping properties of the new models differ significantly from those characterizing the ZZ Ceti models of our previous works, particularly for long periods.

12 pages, 14 figures, 1 table. To be published in Astronomy and Astrophysics

References in corpus (22)

• The Gaia mission
• The Transiting Exoplanet Survey Satellite
• The K2 Mission: Characterization and Early results
• Pulsating White Dwarf Stars and Precision Asteroseismology
• Asteroseismic inferences on GW Vir variable stars in the frame of new PG 1159 evolutionary models
• White dwarf evolutionary sequences for low-metallicity progenitors: The impact of third dredge-up
• Fine Grid Asteroseismology of R548 and G117-B15A
• Asteroseismological measurements on PG 1159-035, the prototype of the GW Vir variable stars
• Asteroseismology of ZZ Ceti stars with fully evolutionary white dwarf models: I. The impact of the uncertainties from prior evolution on the period spectrum
• Discovery of 74 new bright ZZ Ceti stars in the first three years of TESS
• The potential of asteroseismology for probing the core chemical stratification in white dwarf stars
• Probing the structure of Kepler ZZ Ceti stars with full evolutionary models-based asteroseismology
• Toward High Precision Seismic Studies of White Dwarf Stars: Parametrization of the Core and Tests of Accuracy
• Slowly cooling white dwarfs in M13 from stable hydrogen burning
• On the existence of warm H-rich pulsating white dwarfs
• On The Impact Of 22Ne On The Pulsation Periods Of Carbon-Oxygen White Dwarfs With Helium Dominated Atmospheres
• G 207-9 and LP 133-144: light curve analysis and asteroseismology of two ZZ Ceti stars
• Pulsating low-mass white dwarfs in the frame of new evolutionary sequences: V. Asteroseismology of ELMV white dwarf stars
• The impact of Coulomb diffusion of ions on the pulsational properties of DA white dwarfs
• Asteroseismology across the HR diagram
• White-dwarf asteroseismology with the {\sl TESS} space telescope
• Asteroseismic cartography of hydrogen-deficient white dwarfs

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• Gravity modes on rapidly rotating accreting white dwarfs and their variation after dwarf novae
• Extreme mass loss during common envelope evolution: the origin of the double low-mass white dwarf system J2102--4145
• The Fraction of Distilled White Dwarfs with Long-Lived Habitable Zones