2000A&A...356..665R


Query : 2000A&A...356..665R

2000A&A...356..665R - Astronomy and Astrophysics, volume 356, 665-675 (2000/4-2)

NLTE spectral analysis of the sdOB primary of the eclipsing binary system LB 3459 (AA Dor).

RAUCH T.

Abstract (from CDS):

We present a spectral analysis of the sdOB primary star of the binary system LB 3459 based on high-resolution high-S/N optical and UV spectra. The metal abundances are determined by means of state-of-the-art NLTE model atmospheres. We determined Teff=42kK and logg=5.2 within very small error limits. The He (1/125 solar), C (1/265), N (1/33), O (1/12), and Si (1/5) abundances appear strongly depleted while that of Fe and Ni are roughly solar and Mg is strongly enriched by a factor of 6. The spectroscopic distance to LB 3459 is d=396pc. The mass of the primary component of LB 3459 is 0.330M derived from comparisons with theoretical models for sdO stars in the logTeff- logg plane. The mass of the secondary is then 0.066M derived from the mass function. There remains some disagreement between the radius derived from logg and the above mass, and that derived from analysis of the radial-velocity curve and the eclipse curves. LB 3459 is a close binary system which had experienced a common envelope (CE) phase during its evolution. It fits in the ``low mass case B'' scenario of Iben & Livio (1993PASP..105.1373I) and the secondary is a brown dwarf. The spectroscopically determined rotational velocity of the primary is vrot=34±10km/s. Thus even bound rotation (vrot=45.7km/s) cannot be ruled out.

Abstract Copyright:

Journal keyword(s): book reviews - stars: binaries: eclipsing - stars: evolution - stars: fundamental parameters - stars: individual: LB 3459 - book reviews - stars: low-mass, brown 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 - 2022
#notes
1 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 15990 1
2 HD 269696 HS* 05 31 40.3594532592 -69 53 02.153902236 9.74 10.92 11.15     sdB+dM 183 0

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2022.05.22-01:09:52

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