Magnetar behind explosion of extremely bright supernova

Highly magnetised, rapidly spinning neutron stars called magnetars can explain the energy source behind extremely unusual stellar explosions, calculations done by scientists have found.

Stellar explosions known as supernovae usually shine a billion times brighter than the Sun.

Super-luminous supernovae (SLSNe) are a relatively new and rare class of stellar explosions, 10 to 100 times brighter than normal supernovae.

But the energy source of their super-luminosity, and explosion mechanisms are a mystery and remain controversial amongst scientists.

A group of researchers led by Melina Bersten from Kavli Institute for the Physics and Mathematics of the Universe at Tokyo University tested a model that suggests that the energy to power the luminosity of two recently discovered SLSNe, SN 2011kl and ASASSN-15lh, is mainly due to the rotational energy lost by a newly born magnetar.

They analysed two recently discovered super-luminous supernovae: SN 2011kl and ASASSN-15lh.

"These supernovae can be found in very distant universe, thus possibly informing us the properties of the first stars of the universe," said Kavli IPMU principal investigator Ken'ichi Nomoto,

The team performed numerical calculations to explore the magnetar hypothesis.

It found both explosions could be understood in the framework of magnetar-powered supernovae.

"These two extreme super-luminous supernovae put to the test our knowledge of stellar explosions," added Bersten in a paper published in The Astrophysical Journal Letters in January.

To confirm the team's calculations, further observations would need to be carried out when the material ejected by the supernova is expected to become thin.

The most powerful telescopes, including the Hubble Space Telescope, will be required for this purpose.

If correct, these observations will allow scientists to probe the inner part of an exploding object and provide new insight on its origin and evolution of stars in the Universe.