Thermal stability of white dwarfs accreting hydrogen-rich matter and progenitors of type Ia supernovae

Ken'ichi Nomoto, Hideyuki Saio, Mariko Kato, Izumi Hachisu

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137 Citations (Scopus)

Abstract

We revisit the properties of white dwarfs accreting hydrogen-rich matter, by constructing steady state models in which hydrogen shell burning consumes hydrogen at the same rate as the white dwarf accretes it. We obtain steady models for various accretion rates and white dwarf masses. We confirm that these are thermally stable only when the accretion rate is higher than ∼ 10 -7 M yr-1. We show that recent models of quiescent "surface hydrogen burning" for a much wider range of accretion rates result from the use of too large a zone mass in the outer part of the models; hydrogen burning must occur in a much thinner layer. A comparison of the positions on the H-R diagram suggests that most of the luminous supersoft X-ray sources are white dwarfs accreting matter at rates high enough that the hydrogen-burning shell is thermally stable. Implications for the progenitors of Type Ia supernovae are discussed.

Original languageEnglish
Pages (from-to)1269-1276
Number of pages8
JournalAstrophysical Journal
Volume663
Issue number2 I
DOIs
Publication statusPublished - 2007 Jul 10

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Keywords

  • Accretion, accretion disks
  • Binaries: close
  • Novae, cataclysmic variables
  • Stars: evolution
  • Supernovae: general
  • White dwarfs

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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