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RX J2130.6+4710 - an eclipsing white dwarf - M-dwarf binary star

P. F. L. Maxted·T. R. Marsh·L. Morales-Rueda·M. A. Barstow·P. D. Dobbie·M. R. Schreiber·V. S. Dhillon·C. S. Brinkworth
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Abstract

(Abridged) We report the detection of eclipses in the close white-dwarf - M-dwarf binary star RXJ2130.6+4710. We estimate that the spectral type of the M-dwarf is M3.5Ve or M4Ve. We estimate that the effective temperature of the white dwarf is Teff = 18000K +- 1000K. We have used the width of the primary eclipse and duration of totality measured precisely from Ultracam u' data combined with the amplitude of the ellipsoidal effect in the I band and the semi-amplitudes of the spectroscopic orbits to derive masses and radii for the M-dwarf and white dwarf. The M-dwarf has a mass of 0.555 +- 0.023 solar masses and a radius of 0.534 +- 0.053 solar radii, which is a typical radius for stars of this mass. The mass of the white dwarf is 0.554 +- 0.017 solar masses and its radius is 0.0137 +- 0.0014 solar radii, which is the radius expected for a carbon-oxygen white dwarf of this mass and effective temperature RXJ2130.6+4710 is a rare example of a pre-cataclysmic variable star which will start mass transfer at a period above the period gap for cataclysmic variables.

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P. F. L. Maxted, T. R. Marsh, L. Morales-Rueda, M. A. Barstow, P. D. Dobbie, M. R. Schreiber, V. S. Dhillon, C. S. Brinkworth. 2004-09-10. RX J2130.6+4710 - an eclipsing white dwarf - M-dwarf binary star. https://doi.org/10.1111/j.1365-2966.2004.08393.x

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