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arXiv · 1604.04268

The ELM Survey. VII. Orbital Properties of Low Mass White Dwarf Binaries

Warren R. Brown·A. Gianninas·Mukremin Kilic·Scott J. Kenyon·Carlos Allende Prieto
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Abstract

We present the discovery of 15 extremely low mass (5 < log{g} < 7) white dwarf candidates, 9 of which are in ultra-compact double-degenerate binaries. Our targeted ELM Survey sample now includes 76 binaries. The sample has a lognormal distribution of orbital periods with a median period of 5.4 hr. The velocity amplitudes imply that the binary companions have a normal distribution of mass with 0.76 Msun mean and 0.25 Msun dispersion. Thus extremely low mass white dwarfs are found in binaries with a typical mass ratio of 1:4. Statistically speaking, 95% of the white dwarf binaries have a total mass below the Chandrasekhar mass and thus are not Type Ia supernova progenitors. Yet half of the observed binaries will merge in less than 6 Gyr due to gravitational wave radiation; probable outcomes include single massive white dwarfs and stable mass transfer AM CVn binaries.

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Warren R. Brown, A. Gianninas, Mukremin Kilic, Scott J. Kenyon, Carlos Allende Prieto. 2016-04-14. The ELM Survey. VII. Orbital Properties of Low Mass White Dwarf Binaries. https://doi.org/10.3847/0004-637x%2F818%2F2%2F155

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