An international team of astronomers observed what appeared to be a two-explosion outburst from a superluminous supernova (SLSN) event—something that has never been seen before and was previously thought to be impossible.
The Gran Telescopio Canarias in Spain caught sight of the celestial object known as DES14X3taz first going from bright to dim, suggesting an explosion, and then doing it again a few days later, insinuating a second explosion. This is the first time an SLSN was observed from the time it happened until the time it died out.
“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,” team leader Mathew Smith from the University of Southampton in the UK.
Supernovae are very violent explosions that occur when stars “overeat,” or when a star reaches the end of its lifetime and runs out of nuclear fuel, causing mass to flow into its core until it collapses under its own gravitational force.
SLSNs, on the other hand, are much bigger supernovae that have peak luminosities up to ten times greater than an average Type IA supernova, and can keep burning bright for up to six months. Very little is known about the physical nature of these recently discovered supernovae, since only 12 have ever been witnessed so far.
The team believes the double-explosion is likely caused by a magnetar, a neutron star that is so highly magnetic that it can disassemble your very molecular structure if you were to get 1,000km within its range.
The study will help build our incomplete model of how SLSNs form, operate, and die, and researchers are looking into whether the two-explosion supernova is unique to this specific incident or a common occurrence in SLSNs.
“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 said.