The formation and evolution of hydrogen-deficient post-AGB white dwarfs: the emerging chemical profile and the expectations for the PG1159-DB-DQ evolutionary connection

Details The formation and evolution of hydrogen-deficient post-AGB white dwarfs: the emerging chemical profile and the expectations for the PG1159-DB-DQ evolutionary connection The formation and evolution of hydrogen-deficient post-AGB white dwarfs: the emerging chemical profile and the expectations for the PG1159-DB-DQ evolutionary connection

2005-01-31

arxiv.org/abs/astro-ph/0502005v1

Astronomy and Astrophysics

Astrophysics

20 pages, 15 figures. Accepted by Astronomy & Astrophysics

Scientific paper

10.1051/0004-6361:20041965

This paper is designed to 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 M_sun star 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 overshooting, salt fingers and convection is considered. We employed the double-diffusive mixing-length theory of convection for fluids with composition gradients (Grossman & Taam 1996). 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 PG1159 stars and DB white dwarf evolution are studied in the frame 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 PG1159-DB-DQ. In this regard, the implications for the double-layered chemical structure in pulsating DB white dwarfs is investigated. Another aspect of the investigation concerned the consequences of mass-loss episodes during the PG1159 stage for the chemical stratification of the outer layer of DB and DQ white dwarfs.

Affiliated with

Also associated with

No associations

Rating

The formation and evolution of hydrogen-deficient post-AGB white dwarfs: the emerging chemical profile and the expectations for the PG1159-DB-DQ evolutionary connection does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with The formation and evolution of hydrogen-deficient post-AGB white dwarfs: the emerging chemical profile and the expectations for the PG1159-DB-DQ evolutionary connection, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The formation and evolution of hydrogen-deficient post-AGB white dwarfs: the emerging chemical profile and the expectations for the PG1159-DB-DQ evolutionary connection will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-112885