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arXiv · 2004.07556

The closest extremely low-mass white dwarf to the Sun

Adela Kawka·Jeffrey D. Simpson·Stephane Vennes·Michael S. Bessell·Gary S. Da Costa·Anna F. Marino·Simon J. Murphy
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Abstract

We present the orbit and properties of 2MASS J050051.85-093054.9, establishing it as the closest (d ~ 71 pc) extremely low mass white dwarf to the Sun. We find that this star is hydrogen-rich with Teff ~ 10 500 K, log g ~ 5.9, and, following evolutionary models, has a mass of ~ 0.17 solar masses. Independent analysis of radial velocity and TESS photometric time series reveals an orbital period of ~ 9.5 h. Its high velocity amplitude (K ~ 144 km/s) produces a measurable Doppler beaming effect in the TESS light curve with an amplitude of 1 mmag. The unseen companion is most likely a faint white dwarf. J0500-0930 belongs to a class of post-common envelope systems that will most likely merge through unstable mass transfer and in specific circumstances lead to Type Ia supernova explosions.

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Adela Kawka, Jeffrey D. Simpson, Stephane Vennes, Michael S. Bessell, Gary S. Da Costa, Anna F. Marino, Simon J. Murphy. 2020-04-16. The closest extremely low-mass white dwarf to the Sun. https://doi.org/10.1093/mnrasl%2Fslaa068

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