2015A&A...576A.123S


C.D.S. - SIMBAD4 rel 1.7 - 2019.12.06CET14:49:50

2015A&A...576A.123S - Astronomy and Astrophysics, volume 576A, 123-123 (2015/4-1)

An eclipsing post common-envelope system consisting of a pulsating hot subdwarf B star and a brown dwarf companion.

SCHAFFENROTH V., BARLOW B.N., DRECHSEL H. and DUNLAP B.H.

Abstract (from CDS):

Hot subdwarf B stars (sdBs) are evolved, core helium-burning objects located on the extreme horizontal branch. Their formation history is still puzzling because the sdB progenitors must lose nearly all of their hydrogen envelope during the red-giant phase. About half of the known sdBs are in close binaries with periods from 1.2h to a few days, which implies that they experienced a common-envelope phase. Eclipsing hot subdwarf binaries (also called HW Virginis systems) are rare but important objects for determining fundamental stellar parameters. Even more significant and uncommon are those binaries containing a pulsating sdB, since the mass can be determined independently by asteroseismology. Here we present a first analysis of the eclipsing hot subdwarf binary V2008-1753. The light curve shows a total eclipse, a prominent reflection effect, and low-amplitude pulsations with periods from 150 to 180s. An analysis of the light- and radial velocity curves indicates a mass ratio close to q=0.146, an radial velocity semi-amplitude of K=54.6km/s, and an inclination of i=86.8°. Combining these results with our spectroscopic determination of the surface gravity, logg=5.83, the best-fitting model yields an sdB mass of 0.47M and a companion mass of 69MJup. Because the latter mass is below the hydrogen-burning limit, V2008-1753 represents the first HW Vir system that is known to consist of a pulsating sdB and a brown dwarf companion. Consequently, it holds strong potential for better constraining models of sdB binary evolution and asteroseismology.

Abstract Copyright:

Journal keyword(s): subdwarfs - binaries: eclipsing - binaries: spectroscopic - brown dwarfs - stars: fundamental parameters - stars: oscillations

CDS comments: PTF1 J072456+125301 has an incorrect format, see PTF1 J072455.74+125300.5 in Simbad. No coordinates with sufficent accuracy are provided for V2008-1753, not created in Simbad (yet).

Simbad objects: 9

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Number of rows : 9

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 HD 269696 HS* 05 31 40.3598545037 -69 53 02.158611829 9.74 10.92 11.15     sdB+dM 167 0
2 CoRoT-15b BD* 06 28 27.8204 +06 11 10.477   17.012 15.997 15.807   ~ 30 1
3 USNO-B1.0 1028-00171867 EB* 07 24 55.7504821238 +12 53 00.301071647   17.73 18.21 18.19 17.69 ~ 3 0
4 GSC 00196-00617 HS* 08 20 53.5359206605 +00 08 43.500178494   15.03 15.17 15.54 15.91 sdB+dM 27 1
5 BD-07 3477 HS* 12 44 20.2386520980 -08 40 16.848587212   10.46 10.594 10.895   sdB2VIIHe3 243 1
6 V* NY Vir HS* 13 38 48.1466489725 -02 01 49.209465866       13.48   sdB1VIIHe1 183 1
7 PG 1621+476 HS* 16 22 56.6649994821 +47 30 51.124980311   16.07 16.19     sdB+dM 29 0
8 Kepler-451 HS* 19 38 32.6124172412 +46 03 59.139156733   12.17 12.69 12.46 12.399 sdB+dM 50 0
9 NAME V2008-1753 * 20 08 16.3432204430 -17 53 10.636908882   16.8   17.1 17.07 ~ 10 0

    Equat.    Gal    SGal    Ecl

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2019.12.06-14:49:50

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