SN 2006gy

From Wikipedia, the free encyclopedia

Jump to: navigation, search
SN 2006gy

SN 2006gy and the core of its home galaxy, NGC 1260, viewed in x-ray light from the Chandra X-ray Observatory. The NGC 1260 galactic core is on the lower left and SN 2006gy is on the upper right.

Observation data
(Epoch J2000)
Supernova type N/A
Remnant type N/A
Host Galaxy NGC 1260
Constellation Perseus
Right ascension 03h 17m 27.10s[1]
Declination +41º 24' 19.50"[1]
Galactic
coordinates
N/A
Discovery Date 18 September 2006 N/A
Peak magnitude (V) N/A
Physical characteristics
Progenitor N/A
Progenitor type N/A
Colour (B-V) N/A
Notable features N/A


SN 2006gy was an extremely energetic supernova that was discovered around September 18, 2006. It was first observed by R. Quimby and P. Mondol,[1][2] and then studied by several teams of astronomers using facilities that included the Chandra, Lick, and Keck Observatories.[3][4] On May 7, 2007, NASA and several of the astronomers announced the first detailed analyses of the supernova, describing it as the "brightest stellar explosion ever recorded".[5]

Contents

[edit] Characteristics

Illustration of the explosion of SN 2006gy.
Illustration of the explosion of SN 2006gy.

SN 2006gy occurred in a distant galaxy (NGC 1260), approximately 238 million light years (72 megaparsecs) away. Therefore, due to the time it took light from the supernova to reach Earth, the event occurred about 238 million years ago. Preliminary indications are that it was an unusually high-energy supernova of a very large star, around 150 solar masses, possibly of a type referred to as a pair instability supernova. The kinetic energy released by the explosion has been estimated at 1052 ergs [1] making it ten times more powerful than the typical supernova explosion which produces 1051 ergs of energy. Because SN 2006gy has lines of hydrogen, it is classified as a type II supernova although the extreme brightness indicates that it is different from the typical type II supernova.

The supernova's light brightened for about 70 days after discovery, until roughly the beginning of December 2006, and has been slowly decreasing since then. As of early May, 2007, its luminosity is now roughly comparable to the peak luminosity of the prior most luminous observed supernovae.[4]

This diagram illustrates the pair production process that astronomers think triggered the explosion in SN 2006gy. A sufficiently massive star can produce gamma rays of such high energy that some of the photons convert into pairs of electrons and positrons causing a runaway reaction which destroys the star.
This diagram illustrates the pair production process that astronomers think triggered the explosion in SN 2006gy. A sufficiently massive star can produce gamma rays of such high energy that some of the photons convert into pairs of electrons and positrons causing a runaway reaction which destroys the star.

A pair instability supernova can only happen in stars that are very massive—having a range of around 130 to 250 solar masses. The massive star's core can produce extremely high energy gamma rays which have a greater energy than the rest mass of the electron. These gamma rays interact with electromagnetic fields of the atomic nuclei in the star, and produce particle and anti-particle pairs of electrons and positrons. The production of these particles causes some of the energy of the gamma rays to be absorbed into the matter of the star heating the interior of the star, this causes more high energy gamma rays to be produced causing more of the energy to be absorbed. This creates a runaway reaction that eventually causes the star to be blown apart. The explosion blows the star completely apart without leaving a black hole remnant behind.[6] Unlike the usual mechanism for producing type II supernova, there is no collapse phase of the star.

Although the SN 2006gy supernova is intrinsically about ten times as luminous than 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.[7]

Light curve of SN 2006gy (uppermost intermittent squares) compared with other types of supernovae.
Light curve of SN 2006gy (uppermost intermittent squares) compared with other types of supernovae.

[edit] Similarity to Eta Carinæ

Eta Carinæ (η Carinæ or η Car) is a highly luminous hypergiant star located approximately 7,500 light years from Earth in the Milky Way galaxy. Since Eta Carinæ is 32,000 times closer than SN2006gy, the light from it will be almost 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 Carinæ 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,[1] so a similar event at Eta Carinæ 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.[8]

[edit] References

[edit] External links

Wikimedia Commons has media related to:
Personal tools