Once again, astronomers around the world are investigating a stellar explosion, a supernova, in M82, a galaxy 12 million light years away in the constellation Ursa Major. Although supernovae are awesomely destructive, this event is far, far too distant to cause any danger at all to our planet.
Discovered by students and staff at University College London, the supernova is too dim (magnitude 11 when discovered) to see without a telescope of at least 4” aperture, and although it is still getting brighter, it will never be visible to the unaided eye. To locate it, look along the imaginary line between the two end stars on the leading edge of the Plough’s blade (Merak and Dubhe) and Polaris (the North Star), the galaxy M82 (also known as the Cigar Galaxy) along with its companion M81, lies just off this line about a third of the way between the Plough and Polaris. As usual, the supernova is far brighter than its home galaxy, appearing as an extra star. It has been designated SN2014J.
This event is both exciting and important as it is a chance to look at a Type 1a supernova, one of nature’s most violent cataclysms, from comparatively close up. This is one of the closest bright supernovae observed in decades, the last nearby bright supernova was SN1993J in M81 back in 1993.
(For my own pre-supernova observation of M82, see A Summer Night’s Stargazing, I have also written about the mystery object in M82. For a detailed look at another recent Type 1a supernova, including the mechanism that triggers the explosion, see How to see an exploding star).
(Article by Colin Johnston, Science Communicator)