By Ron Cowen
By examining gas lit up by an exploding star, astronomers have obtained new insight into how a common type of supernova erupts.
According to a widely accepted model, the stage is set for a type 1a supernova when a dense, Earthsize star called a white dwarf steals gas from a bloated companion star. When the gas-guzzling white dwarf tips the scales at more than 1.4 times the mass of the sun, it blows to smithereens.