Astronomers have discovered an ultra-massive white dwarf with a unique carbon-hydrogen mixed atmosphere. Named WD J055134.612+413531.09 (WD J0551+4135 for short), this star is located approximately 150 light-years away. It has a mass of 1.14 solar masses and was likely produced from the merger of two white dwarfs in a tight binary system. An artist’s impression of two white dwarfs in the process of merging; depending on the combined mass, the system...
