
Massive white dwarf star is the product of a stellar merger
March 2 (UPI) -- An unusual white dwarf star was formed by a merger between two smaller white dwarfs, according to a new analysis by an international team of astronomers. The ultra-massive white dwarf, WDJ0551+4135, is located 150 light years from Earth. It was first identified by the European Space Agency's Gaia telescope survey. Astronomers keen on studying especially large white dwarfs conducted a followup survey of the star using the William Herschel Telescope. Their observations -- detailed Monday in the journal Nature Astronomy -- revealed an unusual envelope surrounding the star, an atmosphere rich in carbon. "This star stood out as something we had never seen before. You might expect to see an outer layer of hydrogen, sometimes mixed with helium, or just a mix of helium and carbo...