Accurate Masses for the Primary and Secondary in the Eclipsing White Dwarf Binary NLTT 11748

Abstract

We measure the radial velocity curve of the eclipsing detached white dwarf binary NLTT 11748. The primary exhibits velocity variations with a semi-amplitude of 273 km/s and an orbital period of 5.641 hr. We do not detect any spectral features from the secondary star, or any spectral changes during the secondary eclipse. We use our composite spectrum to constrain the temperature and surface gravity of the primary to be Teff = 8690 (140) K and log g = 6.54 (0.05), which correspond to a mass of 0.18 Msol. For an inclination angle of 89.9 deg. derived from the eclipse modeling, the mass function requires a 0.76 Msol companion. The merger time for the system is 7.2 Gyr. However, due to the extreme mass ratio of 0.24, the binary will most likely create an AM CVn system instead of a merger.

ApJ Letters, in press

References in corpus (6)

• Discovery of the Eclipsing Detached Double White Dwarf Binary NLTT 11748
• The Discovery of a Companion to the Lowest Mass White Dwarf
• LP 400-22, A very low-mass and high-velocity white dwarf
• The Runaway White Dwarf LP400-22 Has a Companion
• The double degenerate system NLTT 11748
• No Neutron Star Companion To The Lowest Mass SDSS White Dwarf

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