Other designations SN 2006gy Spectral class IIn Declination +41° 24′ 19.50″ | Event type Supernova Right ascension 03 17 27.10 Epoch J2000 Discovery date 18 September 2006 | |
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Sn 2006gy supernova hypernova animation of
SN 2006gy was an extremely energetic supernova, sometimes referred to as a hypernova or quark-nova, that was discovered on September 18, 2006. It was first observed by Robert Quimby and P. Mondol, and then studied by several teams of astronomers using facilities that included the Chandra, Lick, and Keck Observatories. In May 2007 NASA and several of the astronomers announced the first detailed analyses of the supernova, describing it as the "brightest stellar explosion ever recorded". In October 2007 Quimby announced that SN 2005ap had broken SN 2006gy's record as the brightest ever recorded supernova, and several subsequent discoveries are brighter still. Time magazine listed the discovery of SN 2006gy as third in its Top 10 Scientific Discoveries for 2007.
Contents
- Sn 2006gy supernova hypernova animation of
- Sn 2006gy supernova hypernova image sequence
- Characteristics
- Similarity to Eta Carinae
- References
Sn 2006gy supernova hypernova image sequence
Characteristics
SN 2006gy occurred in a distant galaxy (NGC 1260), approximately 238 million light years (73 megaparsecs) away. Therefore, due to the time it took light from the supernova to reach Earth, the event occurred about 238 million years ago. The energy radiated by the explosion has been estimated at 1051 ergs (1044 J), making it a hundred times more powerful than the typical supernova explosion which radiates 1049 ergs (1042 J) of energy. Although at its peak the SN 2006gy supernova was intrinsically 400 times as luminous as SN 1987A, which was bright enough to be seen by the naked eye, SN 2006gy was more than 1,400 times as far away as SN 1987A, and too far away to be seen without a telescope.
SN 2006gy is classified as a type II supernova because it showed lines of hydrogen in its spectrum, although the extreme brightness indicates that it is different from the typical type II supernova. Several possible mechanisms have been proposed for such a violent explosion, all requiring a very massive progenitor star. The most likely explanations involve the efficient conversion of explosive kinetic energy to radiation by interaction with circumstantial material, similar to a type IIn supernova but on a larger scale. Such a scenario might occur following mass loss of 10 or more M☉ in a luminous blue variable eruption, or through pulsational pair instability ejections. Denis Leahy and Rachid Ouyed, Canadian scientists from the University of Calgary have proposed that SN 2006gy was the birth of a quark star.
Similarity to Eta Carinae
Eta Carinae (η Carinae or η Car) is a highly luminous hypergiant star located approximately 7,500 light years from Earth in the Milky Way galaxy. Since Eta Carinae is 32,000 times closer than SN2006gy, the light from it will be about a billion-fold brighter. It is estimated to be similar in size to the star which became SN2006gy. Dave Pooley, one of the discoverers of SN2006gy, says that if Eta Carinae exploded in a similar fashion, it would be bright enough that one could read by its light here on Earth nights, and would even be visible during the day time. SN2006gy's Apparent magnitude (m) is 15, so a similar event at Eta Carinae will have an m of about −7.5. According to astrophysicist Mario Livio, this could happen at any time, but the risk to life on Earth would be low.
