Astronomers who have long used supernovas as cosmic mile markers to help measure the expansion of the universe now have an answer to the question of what sparks the massive stellar explosions.
“These are such critical objects in understanding the universe,” lead author Marat Gilfanov of the Max Planck Institute for Astrophysics in Germany said Wednesday in describing his team’s study.
“It was a major embarrassment that we did not know how they worked. Now we are beginning to understand what lights the fuse of these explosions.”
Most scientists say Type 1a supernovae are formed when a white dwarf star — the collapsed remnant of an old star — becomes unstable after it exceeds its weight limit.
Instability could come from the merging of two white dwarfs or accretion — a process in which the gravity of the star draws in enough material from a sun-like companion.
Using NASA’s Chandra X-ray Observatory, Gilfanov and his team studied the supernovas in five nearby elliptical galaxies and the central region of the Andromeda galaxy.