Discovery of a hot ultramassive rapidly rotating DBA White Dwarf

Abstract

We report the discovery of a nearby massive white dwarf with He-H atmosphere. The white dwarf is located at a distance of $74.5\pm 0.9$ pc. Its radius, mass, effective temperature, H/He ratio and age are $R=2500\pm 100$ km, $M=1.33\pm 0.01$ ${\mathrm{M}}_{\odot }$, $T_{\mathrm{eff}}=31200\pm 1200$ K, $H/He\sim 0.1$ and $330\pm 40$ Myr, respectively. The observed spectrum is redshifted by $V_{\mathrm{r}}=+240\pm 15$ km s${}^{-1},$ which is mostly attributed to the gravitational redshift. The white dwarf shows a regular stable photometric variability with amplitude $\Delta g\approx 0.06^{\mathrm{m}}$ 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.

5 pages, 6 figures, submitted

References in corpus (12)

• The Gaia mission
• The Evolution of Compact Binary Star Systems
• eROSITA Science Book: Mapping the Structure of the Energetic Universe
• Slowing the Spins of Stellar Cores
• Evidence for sub-Chandrasekhar-mass progenitors of Type Ia supernovae at the faint end of the width-luminosity relation
• The Viscous Evolution of White Dwarf Merger Remnants
• Hot DB White Dwarfs from the Sloan Digital Sky Survey
• The Trouble with the Local Bubble
• An ultra-massive white dwarf with a mixed hydrogen-carbon atmosphere as a likely merger remnant
• A deep test of radial differential rotation in a helium-atmosphere white dwarf: I. Discovery of pulsations in PG 0112+104
• Spiral Disk Instability Can Drive Thermonuclear Explosions in Binary White Dwarf Mergers
• A young contracting white dwarf in the peculiar binary HD 49798/RX J0648.0--4418?