The shortest period detached white dwarf + main-sequence binary
Parsons, S. G., Marsh, T. R., Gaensicke, B. T. (Boris T.), Dhillon, V. S., Copperwheat, C. M., Littlefair, S. P., Pyrzas, S., Drake, A. J., Koester, Detlev, 1941-, Schreiber, Matthias R. and Rebassa-Mansergas, A.. (2012) The shortest period detached white dwarf + main-sequence binary. Monthly Notices of the Royal Astronomical Society, Vol.419 (No.1). pp. 304-313. ISSN 0035-8711Full text not available from this repository.
Official URL: http://dx.doi.org/10.1111/j.1365-2966.2011.19691.x
We present high-speed ULTRACAM and SOFI photometry and X-shooter spectroscopy of the recently discovered 94-min orbital period eclipsing white dwarf/main-sequence binary SDSS J085746.18+034255.3 (CSS 03170) and use these observations to measure the system parameters. We detect a shallow secondary eclipse and hence are able to determine an orbital inclination of i= 85?5 ± 0?2. The white dwarf has a mass of 0.51 ± 0.05 Msun and a radius of 0.0247 ± 0.0008 Rsun. With a temperature of 35 300 ± 400 K the white dwarf is highly overinflated if it has a carbon-oxygen core; however, if it has a helium core then its mass and radius are consistent with evolutionary models. Therefore, the white dwarf in SDSS J085746.18+034255.3 is most likely a helium core white dwarf with a mass close to the upper limit expected from evolution. The main-sequence star is an M8 dwarf with a mass of 0.09 ± 0.01 Msun and a radius of 0.110 ± 0.004 Rsun placing it close to the hydrogen burning limit. The system emerged from a common envelope ˜20 million years ago and will reach a semidetached configuration in ˜400 million years, becoming a cataclysmic variable with a period of 66 min, below the period minimum.
|Item Type:||Journal Article|
|Subjects:||Q Science > QB Astronomy|
|Divisions:||Faculty of Science > Physics|
|Library of Congress Subject Headings (LCSH):||Eclipsing binaries, White dwarf stars, Low mass stars|
|Journal or Publication Title:||Monthly Notices of the Royal Astronomical Society|
|Official Date:||January 2012|
|Page Range:||pp. 304-313|
|Access rights to Published version:||Restricted or Subscription Access|
|Funder:||Science and Technology Facilities Council (Great Britain) (STFC), Fondo Nacional de Desarrollo Científico y Tecnológico (Chile) (FONDECYT)|
|Grant number:||3110049 (FONDECYT), 1100782 (FONDECYT)|
Baraffe I., Chabrier G., 1996, ApJ, 461, L51
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