First-ever evidence of stellar 'double detonation' captured

For the first time, astronomers have captured stunning visual evidence of a star double-detonating itself to death. The twin eruption was discovered by scientists studying two concentric rings of calcium that surround SNR 0509-67.5, a remnant of a star that met its explosive demise in a type la supernova centuries ago. And the discovery isn’t just a pretty picture. The researchers who made it say that much of our knowledge of how the universe expands — a major controversy in cosmology — depends on reliably measuring this type of supernova, which is also the primary source of iron throughout the cosmos. For these reasons, “the explosions of white dwarfs play a crucial role in astronomy,” said Priyam Das, a graduate student at the University of New South Wales Canberra in Australia. “Yet despite their importance, the longstanding puzzle of the exact mechanism triggering their explosion remains unsolved.”

- WORDS BEN TURNER

Type la supernovae occur when material from one star is stolen by the husk of a co-orbiting dead star, known as a white dwarf, leading to a gigantic thermonuclear explosion. Yet not all of the ways that white dwarfs detonate are accounted for. Astronomers assume that these white dwarfs steadily snatch their neighbouring star’s material, accumulating it until they reach a critical mass, the Chandrasekhar limit, and explode. But astronomers have found hints suggesting that this isn't the only way the husks blow up.