A never-before-seen partial ‘supernova’ sent the corpse of this star gliding across the galaxy


An intimate pair of distant stars had a violent fall, sending the two million miles a day to opposite ends of the universe. Relationships, huh?

In 2015, astronomers discovered one of those stars (called SDSS J1240 + 6710) crossing the Milky Way. The star’s brightness and composition suggested it was a white dwarf – the decaying, Earth-sized shell of a once-giant red giant. But something about the fugitive star’s atmosphere seemed out of place. Typical white dwarfs have external atmospheres made almost entirely of hydrogen and helium; The atmosphere of this star had none of the elements.