Warwick: Two Stars Merged to Form Massive White Dwarf
Posted: Mon Mar 02, 2020 6:45 pm
Two Stars Merged to Form Massive White Dwarf
University of Warwick, UK | 2020 Mar 02
An Ultra-Massive White Dwarf with a Mixed Hydrogen-Carbon Atmosphere as a Likely Merger Remnant ~ M.A. Hollands et al
University of Warwick, UK | 2020 Mar 02
White dwarf that is two-thirds the size of the Earth is actually two stars merged; Scientists spotted unusual phenomena by the star's spectral signature; Star is massive enough to account for two average sized white dwarfs and may just about have failed to explode as a supernova; Provides evidence for the existence of more ultra-massive white dwarfs with hidden merger histories.
A massive white dwarf star with a bizarre carbon-rich atmosphere could be two white dwarfs merged together according to an international team led by University of Warwick astronomers, and only narrowly avoided destruction.Artist's impression of two white dwarfs in the process of merging. Depending on the
combined mass, the system may explode in a thermonuclear supernova, or coalesce
into a single heavy white dwarf, as with WDJ0551+4135.
Credit: University of Warwick/Mark Garlick
They have discovered an unusual ultra-massive white dwarf around 150 light years from us with an atmospheric composition never seen before, the first time that a merged white dwarf has been identified using its atmospheric composition as a clue.
The discovery ... could raise new questions about the evolution of massive white dwarf stars and on the number of supernovae in our galaxy.
This star, named WDJ0551+4135, was identified in a survey of data from the European Space Agency’s Gaia telescope. The astronomers followed up with spectroscopy taken using the William Herschel Telescope, focusing on those white dwarfs identified as particularly massive – a feat made possible by the Gaia mission. By breaking down the light emitted by the star, the astronomers were able to identify the chemical composition of its atmosphere and found that it had an unusually high level of carbon present. ...
An Ultra-Massive White Dwarf with a Mixed Hydrogen-Carbon Atmosphere as a Likely Merger Remnant ~ M.A. Hollands et al
- Nature Astronomy (online 02 Mar 2020) DOI: 10.1038/s41550-020-1028-0