The shortest period detached white dwarf + main-sequence binary
Parsons, S. G., Marsh, T. R., Gaensicke, B. T., Dhillon, V. S., Copperwheat, C. M., Littlefair, S. P., Pyrzas, S., Drake, A. J., Koester, Detlev, 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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