The formation and evolution of hydrogen-deficient post-AGB white dwarfs: The emerging chemical profile and the expectations for the PG 1159-DB-DQ evolutionary connection
By L. Althaus, A. Serenelli, J. A. Panei, A. Córsico, E. García–Berro, C. Scóccola. 2005
163 citations recorded by the source corpus.
We explore the formation and evolution of hydrogen-deficient post-AGB white dwarfs. To this end, we compute the complete evolution of an initially 2.7 Mstar from the zero-age main sequence through the thermally pulsing and mass-loss phases to the white dwarf stage. Particular attention is given to the chemical abundance changes during the whole evolution. A time-dependent scheme for the simultaneous treatment of abundance changes caused by nuclear reactions, diffusive overshoot- ing, salt fingers and convection is considered. We employed the double-diffusive mixing-length theory of convection for fluids with composition gradients. The study can therefore be considered as a test of its performance in low-mass stars. Also, time- dependent element diffusion for multicomponent gases is taken into account during the white dwarf evolution. The evolutionary stages corresponding to the last helium thermal pulse on the early white-dwarf cooling branch and the following born-again episode are carefully explored. Relevant aspects for PG 1159 stars and DB white dwarf evolution are studied in the framework of these new evolutionary models that take into account the history of the white dwarf progenitor. The scope of the calculations is extended to the domain of the helium-rich, carbon-contaminated DQ white dwarfs with the aim of exploring the plausibility of the evolutionary connection PG 1159-DB-DQ. In this regard, the implications for the double-layered chemical structure in pulsating DB white dwarfs is investigated. We examine the consequences of mass-loss episodes during the PG 1159 stage for the chemical stratification of the outer layer of DB and DQ white dwarfs.
Subfields: Astronomy and Astrophysics
View Paper: https://www.semanticscholar.org/paper/7df02f5ce79d456e9a191c1f7bca9b348efba7b4
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In Astronomy and Astrophysics
Citations in the corpus
- NEW COOLING SEQUENCES FOR OLD WHITE DWARFS (2010, methodology): “…with 34 thermonuclear reaction rates of the pp chains, CNO bi-cycle, helium-burning, and carbon ignition that are identical to those described in Althaus et al. (2005b), with the exception of the reaction 12C + p → 13N + γ → 13C + e+ + νe and 13C(p, γ )14N, for which we adopted the rate of…”
- On the Spectral Evolution of Hot White Dwarf Stars. I. A Detailed Model Atmosphere Analysis of Hot White Dwarfs from SDSS DR12 (2020, background): “…is the result of a late helium-shell flash, during which the superficial hydrogen is deeply mixed in the helium envelope and almost entirely burned, while significant quantities of carbon and oxygen are dredged up to the surface (Herwig et al. 1999; Althaus et al. 2005; Werner & Herwig 2006).”
- Evolutionary and pulsational properties of white dwarf stars (2010, methodology): “On the theoretical front, recent important progress in the numerical modeling of PG 1159 stars (Althaus et al. 2005a; Miller Bertolami &Althaus 2006) has paved the way for unprecedented asteroseismological inferences forthe mentioned stars (Córsico et al. 2007a, 2007b, 2008, 2009b).”
- Double-detonation sub-Chandrasekhar supernovae: can minimum helium shell masses detonate the core? (2010, background): “4.1 and Table 2) where the carbon fraction is expected to be higher than in the innermost region (see, e.g., Althaus et al. 2005).”
- Pulsating White Dwarf Stars and Precision Asteroseismology (2008, background): “There is a small dependency on the mass of the star, determined from comparison of atmospheric parameters to evolutionary models (e.g., Wood 1995, Althaus et al. 2005), both theoretically (e.g., Bradley 1996) and observationally (Giovannini et al. 1998; Gianninas, Bergeron & Fontaine 2006).”