Type Ia supernovae are used as cosmic yardsticks to measure distances in the Universe. That’s because they always explode with roughly the same intensity. The theory goes: Type Ia supernovae occur when a white dwarf star consumes a specific amount of material from a binary partner. It can’t hold the extra mass, and so it explodes.
Now observations by the European Southern Observatory’s Very Large Telescope have turned up evidence of this stream of material in the region around a recently exploded Type Ia supernova, lending evidence to this theory.
The supernova is SN 2006X, which exploded 70 million light-years away in the spiral galaxy M100. The ESO observations turned up traces of material that would have been around before the explosion. This material was arranged in shells around the central explosion. Since the explosion is expanding out at a rate of 50 km/s, astronomers believe the material was ejected about 50 years before the explosion.
This 50 km/s velocity of material is important, because it matches speed of stellar wind pumped out by red giant stars. As the expanding sphere of supernova wreckage crashes into this material from the red giant, it gets absorbed in a way that astronomers can distinguish.
Original Source:ESO News Release