Query : 2009A&A...493.1067G

2009A&A...493.1067G - Astronomy and Astrophysics, volume 493, 1067-1073 (2009/1-3)

Testing the evolution of the DB white dwarf GD 358: first results of a new approach using asteroseismology.


Abstract (from CDS):

We present a new method that investigates the evolutionary history of the pulsating DB white dwarf GD 358 using asteroseismology. This is done considering the internal C/O profile, which describes the relative abundances of carbon and oxygen from the core of the star to its surface. Different evolutionary channels lead to the generation of different C/O profiles, and these affect the pulsation periods. We used the C/O profiles associated with white dwarfs that evolved through binary evolution channels where the progenitor experienced one or two episodes of mass loss during one or two common envelope (CE) phases, and two profiles from single-star evolution. We computed models using these different profiles and used a genetic algorithm (GA) to optimize the search in the parameter space for the best fit to the observed pulsation periods. We used three-parameter models, adjusting the stellar mass (M*), the effective temperature (Teff), and the helium mass of the external layer (MHe). Our results suggest that binary evolution profiles may provide a better match to the pulsation periods of GD 358. The best fit to the observations is obtained using a profile related to an evolutionary history where two episodes of mass loss happen during two CE phases, the first during the RGB (red giant branch) stage. The values obtained are Teff=24300 K, M*=0.585 M, and log(MHe/M*)=-5.66. The best-fit model has a mass close to the mean mass for DB white dwarfs found in various works and a temperature consistent with UV spectra obtained with the IUE satellite.

Abstract Copyright:

Journal keyword(s): stars: oscillations - stars: white dwarfs - stars: individual: GD 358 - stars: evolution - stars: interiors

Simbad objects: 4

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Number of rows : 4
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 V* SW LMi WD* 09 57 49.4086247376 +33 59 23.691674976   17       DB 56 0
2 V* AM CVn CV* 12 34 54.6231062664 +37 37 44.120620056   14.02 14.13 14.47   DBnnp 403 0
3 GALEX J142625.6+575218 WD* 14 26 25.7057882376 +57 52 18.263585532   19.7 19.37 19.5   DQ 29 1
4 GD 358 WD* 16 47 18.3925183824 +32 28 32.862804384 12.511 13.530 13.653 13.752 13.852 DB2 348 0

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