The closest extremely low-mass white dwarf to the Sun

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....

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Bibliographic Details
Main Authors: Kawka, Adela, Simpson, Jeffrey D, Vennes, Stephane, Bessell, Michael S, Da Costa, Gary S, Marino, Anna F, Murphy, Simon J
Format: Journal Article
Language:English
Published: OXFORD UNIV PRESS 2020
Subjects:
Online Access:http://dx.doi.org/10.1093/mnrasl/slaa068
http://hdl.handle.net/20.500.11937/80039
Description
Summary: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.