Modeling He-rich subdwarfs through the hot-flasher Scenario

Details Modeling He-rich subdwarfs through the hot-flasher Scenario Modeling He-rich subdwarfs through the hot-flasher Scenario

2008-08-26

arxiv.org/abs/0808.3580v3

A&A, 491, 253-265 (2008)

Astronomy and Astrophysics

Astrophysics

13 pages, including 8 figures and 6 tables. Accepted for publication in A&A. Replaced to match the final version, including a

Scientific paper

10.1051/0004-6361:200810373

We present 1D numerical simulations aimed at studying the hot-flasher scenario for the formation of He-rich subdwarf stars. Sequences were calculated for a wide range of metallicities and physical assumptions, such as the stellar mass at the moment of the helium core flash. This allows us to study the two previously proposed flavors of the hot-flasher scenario ("deep" and "shallow" mixing cases) and to identify a third transition type. Our sequences are calculated by solving simultaneously the mixing and burning equations within a diffusive convection picture, and in the context of standard mixing length theory. We are able to follow chemical evolution during deep-mixing events in which hydrogen is burned violently, and therefore able to present a homogeneous set of abundances for different metallicities and varieties of hot-flashers. We extend the scope of our work by analyzing the effects of non-standard assumptions, such as the effect of chemical gradients, extra-mixing at convective boundaries, possible reduction in convective velocities, or the interplay between difussion and mass loss. Particular emphasis is placed on the predicted surface properties of the models. We find that the hot-flasher scenario is a viable explanation for the formation and surface properties of He-sdO stars. Our results also show that, during the early He-core burning stage, element diffusion may produce the transformation of (post hot-flasher) He-rich atmospheres into He-deficient ones. If this is so, then we find that He-sdO stars should be the progenitors of some of the hottest sdB stars.

Affiliated with

Also associated with

No associations

Rating

Modeling He-rich subdwarfs through the hot-flasher Scenario 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 Modeling He-rich subdwarfs through the hot-flasher Scenario, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Modeling He-rich subdwarfs through the hot-flasher Scenario will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-527783