Astronomers team led by Matt Nicholl from the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge have found an extraordinarily bright supernova “SN 2017egm” in a surprising location. This ‘heavy metal’ supernova discovery challenges current ideas of how and where such super-charged supernovas occur.
Supernovas are some of the most energetic events in the Universe. When a massive star runs out of fuel, it can collapse onto itself and create a spectacular explosion that briefly outshines an entire galaxy, dispersing vital elements into space.
In the past decade, astronomers have discovered about fifty supernovas, out of the thousands known, that are particularly powerful. These explosions are up to 100 times brighter than other supernovas caused by the collapse of a massive star.
SN 2017egm is located in a spiral galaxy about 420 million light years from Earth, making it about three times closer than any other superluminous supernova previously seen. Dong realized that the galaxy was very surprising, as virtually all known superluminous supernovas have been found in dwarf galaxies that are much smaller than spiral galaxies like the Milky Way.