We report the discovery of a nearby massive white dwarf with He-H atmosphere. The white dwarf is located at a distance of 74.5±0.9 pc. Its radius, mass, effective temperature, H/He ratio and age are R=2500±100 km, M=1.33±0.01M⊙, Teff=31200±1200 K, H/He∼0.1 and 330±40 Myr, respectively. The observed spectrum is redshifted by Vr=+240±15 km s−1, which is mostly attributed to the gravitational redshift. The white dwarf shows a regular stable photometric variability with amplitude Δg≈0.06m and period P=353.456 s suggesting rapid rotation. This massive, hot and rapidly rotating white dwarf is likely to originate from the merging of close binary white dwarf system that avoided explosion in a thermonuclear type Ia supernova at the Carboniferous Period of the Earth history.
@article{arxiv.2007.06514,
title = {Discovery of a hot ultramassive rapidly rotating DBA White Dwarf},
author = {M. S. Pshirkov and A. V. Dodin and A. A. Belinski and S. G. Zheltoukhov and A. A. Fedoteva and O. V. Voziakova and S. A. Potanin and S. I. Blinnikov and K. A. Postnov},
journal= {arXiv preprint arXiv:2007.06514},
year = {2020}
}