An ultra-massive white dwarf is the result of a merger between two normal white dwarfs
An article published in the journal “Nature Astronomy” reports a study on a white dwarf out of the ordinary cataloged as WD J055134.612+413531.09, or simply WD J0551+4135. A team of astronomers coordinated by the British University of Warwick examined this white dwarf’s characteristics using data collected by ESA’s Gaia space probe and the William Herschel Telescope concluding that its atmosphere’s particular chemical composition indicates that it’s the result the merger of two medium-mass white dwarfs. WD J0551+4135 has a mass slightly higher than that of the Sun, remarkable for that type of object to the point that it was called an ultra-massive white dwarf. If it had a slightly larger mass it would probably have exploded in a supernova following the merger.
