 SN 2006gy and the core of its home galaxy,NGC 1260, viewed inx-ray light from theChandra X-ray Observatory. The NGC 1260 galactic core is on the lower left and SN 2006gy is on the upper right. | |
| Event type | Hypernova |
|---|---|
| IIn[1] | |
| Date | c. 238 million years ago (discovered 18 September 2006 byRobert Quimby and P. Mondol) |
| Constellation | Perseus |
| Right ascension | 03h 17m 27.10s[2] |
| Declination | +41° 24′ 19.50″[2] |
| Epoch | J2000 |
| Galactic coordinates | 150.2568 -13.5916 |
| Distance | c. 238 millionly[3] |
| Host | NGC 1260 |
| Progenitor | Hypergiant |
| Notable features | is located 2.0" W and 0.4" N of the center of NGC 1260 |
| Peakapparent magnitude | +14.2 |
| Other designations | SN 2006gy |
 Related media on Commons | |
SN 2006gy was an extremely energeticsupernova, also referred to as ahypernova,[4] that was discovered on September 18, 2006. It was first observed byRobert Quimby and P. Mondol,[2][5] and then studied by several teams ofastronomers using facilities that included theChandra,Lick, andKeckObservatories.[6][7] In May 2007,NASA and several of the astronomers announced the first detailed analyses of the supernova, describing it as the "brighteststellar explosion ever recorded".[8] In October 2007, Quimby announced thatSN 2005ap had broken SN 2006gy's record as the brightest-ever recorded supernova, and several subsequent discoveries are brighter still.[9][10]Time magazine listed the discovery of SN 2006gy as third in its Top 10 Scientific Discoveries for 2007.[11]
SN 2006gy occurred in thegalaxyNGC 1260, approximately 238 millionlight-years (73megaparsecs) away.[3] The energy radiated by the explosion has been estimated at 1051ergs (1044J), 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 asluminous asSN 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 thus too far away to be seen without atelescope.
SN 2006gy is classified as atype 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.[10] One promising explanation involves the efficient conversion of explosive kinetic energy to radiation by interaction with a massive circumstellar shell, similar to atype IIn supernova but on a larger scale. Such a scenario might occur following mass loss of 10 or more M☉ in aluminous blue variable eruption, throughpulsational pair instability ejections,[12] or a common envelope event[13]. Denis Leahy and Rachid Ouyed, Canadian scientists from theUniversity of Calgary, have proposed that SN 2006gy was aquark-nova, heralding the birth of aquark star.[14]
Eta Carinae (η Carinae or η Car) is a highly luminoushypergiant star located approximately 7,500 light-years from Earth in theMilky Way galaxy. Since Eta Carinae is 32,000 times closer than SN 2006gy, the light from it will be about a billion-fold brighter. It is estimated to be similar in size to the star which became SN 2006gy. Dave Pooley, one of the discoverers of SN 2006gy, says that if Eta Carinae exploded in a similar fashion, it would be bright enough that one could read by its light on Earth at night, and would even be visible during the daytime. SN 2006gy'sapparent magnitude (m) was 15,[2] so a similar event at Eta Carinae will have anm of about −7.5. According to astrophysicistMario Livio, this could happen at any time, but the risk to life on Earth would be low.[15]
