Query : 2009A&A...494.1021A

2009A&A...494.1021A - Astronomy and Astrophysics, volume 494, 1021-1024 (2009/2-2)

On the origin of white dwarfs with carbon-dominated atmospheres: the case of H1504+65.


Abstract (from CDS):

We explore different evolutionary scenarios to explain the helium deficiency observed in H1504+65, the most massive known PG1159 star. We concentrate mainly on the possibility that this star could be the result of mass loss shortly after its born-again and during its subsequent evolution through the [WCL] stage. This possibility is consistent with observational evidence of extensive mass-loss events in Sakurai's object and is in line with the finding that these mass losses give rise to PG1159 models with thin helium-rich envelopes and high rates of period change, as demanded by the pulsating star PG1159-035. We compute the post-born-again evolution of massive sequences by taking into account different mass-loss rate histories. Our results show that stationary winds during the post-born-again evolution fail to remove completely the helium-rich envelope and are therefore unable to explain the helium deficiency observed in H1504+65. Stationary winds during the Sakurai and [WCL] stages remove at most half of the envelope that survives the violent hydrogen burning during the born-again phase. In view of our results, the proposed evolutionary sequence of born-again stars to H1504+65 and then to white dwarfs with carbon-rich atmospheres is difficult to reproduce unless the entire helium-rich envelope is ejected by non-stationary mass-loss episodes during the Sakurai stage.

Abstract Copyright:

Journal keyword(s): stars: interiors - stars: evolution - stars: white dwarfs - stars: AGB and post-AGB

Simbad objects: 3

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Number of rows : 3
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 V* GW Vir WD* 12 01 45.9731868264 -03 45 40.628670300   14.87 15.04     DOQZ1 484 0
2 PG 1501+664 WD* 15 02 09.6299323152 +66 12 19.148868324   16.07 16.37     DZQ1 156 0
3 V* V4334 Sgr CV* 17 52 32.69352 -17 41 08.0160           F2Ia 363 0

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