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M82 Supernova

posted 24 Jan 2014, 10:58 by Andrew Sellek
On Tuesday evening, staff and students at University College London (UCL) observatory observed a supernova occur in M82 (the light started to reach us a few days earlier but took time for it to brighten). The distance to this galaxy means it happened 11.5 million years ago but it is the closest one observed for 20 years.

A supernova usually marks the end of the life of a large star. With most of the fuel used for nuclear fusion exhausted, the star produces less energy and so the "radiation pressure" can no longer resist the gravitational force. The star collapses in, before the outer layers rebound and are thrown off in a high-energy explosion which creates some of the elements heavier than iron. 

However, this occurrence seems to be a White Dwarf Supernova or Type Ia supernova, where the explosion is caused by a white dwarf, the remnant of a lower mass star having accreted material, often from a companion, until  it became massive enough to trigger a supernova.

The supernova has been assigned the name SN 2014J.

Not only is it an excellent object for scientific research into dark energy by the use of neutrinos, and as a Type Ia supernova a "standard candle" whose exact brightness is known allowing us to measure distances across the universe, but it is well timed for our observational evening next month, since it is one of our focus objects for the session! Currently at magnitude, 11.2, predictions suggest that it will reach peak brightness in the first week of February