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New supernova stuns astronomers

Jenny Winder, News Writer
Jan 23, 2014, 8:00 UTC

Sen—A new supernova has appeared in the galaxy Messier 82 (M82), the Cigar or Starburst Galaxy. At about 11.4 million light-years away this is one of the closest stellar explosions for years.

News of the object, discovered on January 21 by tutor Dr Steve Fossey and his students, of University College London, first appeared on the Central Bureau for Astronomical Telegrams "Transient Objects Confirmation Page".

Fossey explained, "You look at these galaxies so often that they become familiar. When I looked at the image we'd got of M82, it struck me that it didn't look quite right. So I got the students to help check that it wasn’t an asteroid or something in the way. Then when I felt confident that this was a supernova, I emailed an alert to the International Astronomical Union so that other observatories could check it out."

UCL team’s discovery image, right. Earlier image of the galaxy, left. Image credit: UCL/University of London Observatory/Steve Fossey/Ben Cooke/Guy Pollack/Matthew Wilde/Thomas Wright.

Estimates suggest it is currently at magnitude +11 to +12, meaning it can be seen through even a modest telescope, but it could reach magnitude 8, making it visible through binoculars.

A Type 1A supernova occurs when a white dwarf star pulls hydrogen gas from a nearby companion. When the white dwarf reaches a mass 1.4 times that of the Sun, it can't support itself and the star collapses in a runaway fusion reaction.

Type 1a supernovae like this are used to measure distances across the Universe and led to the discovery that the expansion of the Universe is accelerating, which implies the Universe consists of 70 per cent Dark Energy.

Even though M82 is a very popular target with astronomers it appears that it took a while for the supernova to be spotted, as early as January 16 it had already brightened to magnitude 13.9.

Nick Howes, Faulkes Telescope Pro Am Programme Manager and one of the Team of observers from Remanzacco Observatory in Italy, who performed some of the follow-up observations, told Sen, "Supernova of this type occurring this close will provide astronomers with a wealth of data to help investigate dark energy"

"What's amazing is that so many people image M82 all the time, and yet it seems like this event was missed by all for up to a week."

The closest supernova of recent times was SN1987A in 1987 in the Milky Way’s companion galaxy the Large Magellanic Cloud.