2005A&A...435..649M


C.D.S. - SIMBAD4 rel 1.7 - 2021.06.17CEST19:18:25

2005A&A...435..649M - Astronomy and Astrophysics, volume 435, 649-655 (2005/5-4)

An asteroseismic test of diffusion theory in white dwarfs.

METCALFE T.S., NATHER R.E., WATSON T.K., KIM S.-L., PARK B.-G. and HANDLER G.

Abstract (from CDS):

The helium-atmosphere (DB) white dwarfs are commonly thought to be the descendants of the hotter PG 1159 stars, which initially have uniform He/C/O atmospheres. In this evolutionary scenario, diffusion builds a pure He surface layer which gradually thickens as the star cools. In the temperature range of the pulsating DB white dwarfs (Teff∼25000K) this transformation is still taking place, allowing asteroseismic tests of the theory. We have obtained dual-site observations of the pulsating DB star CBS 114, to complement existing observations of the slightly cooler star GD 358. We recover the 7 independent pulsation modes that were previously known, and we discover 4 new ones to provide additional constraints on the models. We perform objective global fitting of our updated double-layered envelope models to both sets of observations, leading to determinations of the envelope masses and pure He surface layers that qualitatively agree with the expectations of diffusion theory. These results provide new asteroseismic evidence supporting one of the central assumptions of spectral evolution theory, linking the DB white dwarfs to PG 1159 stars.

Abstract Copyright:

Journal keyword(s): stars: evolution - stars: individual: CBS 114 - stars: individual: GD 358 - stars: interiors - stars: oscillations - white dwarfs

Simbad objects: 2

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Number of rows : 2

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 V* SW LMi WD* 09 57 49.4085937403 +33 59 23.693730968   17       DB 50 0
2 GD 358 WD* 16 47 18.3926893312 +32 28 32.865420612 12.511 13.530 13.653 13.752 13.852 DB2 324 0

    Equat.    Gal    SGal    Ecl

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2021.06.17-19:18:25

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