supernova exploded twice!!!!!!!!!!!!!

Most supernovae explode only once, but a newly found superluminous star did something truly bizarre: it exploded twice. A recently discovered class of supernovae called superluminous supernovae (SLSN) are brighter and longer-lasting. Only a dozen or so have been found, and using the Gran Telescopio CANARIAS (GTC), astronomers have found evidence of another, but reveals surprising behavior. It seems to have exploded not only once, but twice. The findings are published in The Astrophysical Journal Letters. 

There are several different types of supernovae; the most well known type Ia, where a white dwarf star absorbs mass from another star or collides with another white dwarf which causes a thermonuclear explosion as its mass becomes unstable. The other types of supernovae are caused when massive stars use up all their fuel and can no longer fuse atoms together in its core. They then collapse under their own gravity causing a supernova.

The research has revealed that the supernova had an initial increase in brightness, declined for a few days, then increased again even stronger than before.

"Superluminous supernovas are up to a hundred times more energetic than type Ia supernovae because they can remain bright for up to six months before fading, rather than just a few weeks," explains Mathew Smith, the lead author of the study and a postdoctoral researcher at the University of Southampton, in a press release. "What we have managed to observe, which is completely new, is that before the major explosion, there is a shorter, less luminous outburst, which we can pick out because it is followed by a dip in the light curve, and which lasts just a few days."

This is the first time something like this has ever been observed in a supernova.

"From our data, we have tried to determine if this is a characteristic unique to this object, or whether it is a common feature of all superluminous supernovae, but has not been observed before, which is perfectly possible given their unpredictable nature," Smith says.

Discovered on December 21, 2014, the object was given the name DES14X3taz by the Dark Energy Survey (DES) which studies the expansion of the universe through dark energy, but occasionally detects supernovae and other transient phenomenon.