Astronomers Observe A Supernova Colliding With Its Companion Stars

Supernova is one of the most spectacular events in the universe. Supernovae occur when small dense stars known as white dwarfs explode with unimaginable intensity. These kinds of explosions occur once in a century and needless to say such incidents are very rarely visible.

On 3rd May 2014, a team of observers led by Shrinivas Kulkarni at iPTF (intermediate Palomar Transient Factory) discovered a type Ia supernova in a nearby galaxy IC831 about 300 million light years away. The astronomers were very skeptical about the reasons behind formation of Supernova from a white dwarf, but this new observation has given birth of two different theories regarding the formation of Supernovae.

There are two competing origin theories of Supernova. In both the theories one common point of view is that white dwarf explodes in one of the pair of two stars with common centre of mass. The first theory also known as double-degenerate model proposes that the companion of the exploded white dwarf is also a white dwarf and thus two similar white dwarfs initiate a supernova. The second theory, known as single-degenerate model opines that the second star may be a sun like star or a red giant. The huge gravitational attraction of the white dwarf pulls out materials from the second star and creates a nuclear explosion inside the white dwarf.

The information collected and images analyzed by the iPTF member Yi Cao and Caltech graduate students show that single-degenerate model is very suitable with the observed happenings in the supernova on 3rd May 2014. Cao and his team members used UV light analysis to further spot this type of Supernova-Companion collision in the universe. However, astronomers don’t rule out the occurrences of double-degenerate model of explosions.

Astronomers are now on search for more and more la Supernova to make sure that both theories are very much valid in different situations.