SN 2006gy

Infobox Supernova
name = SN 2006gy


caption = 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.
epoch = J2000
type = N/A
SNRtype = N/A
host = NGC 1260
constellation = Perseus
ra = 03h 17m 27.10s
dec = +41º 24' 19.50"
gal = 150.2568 -13.5916
discovery = 18 September 2006
iauc = N/A
mag_v = +15.0
distance = 268,000,000 Ly (72 Mpc)
progenitor = N/A
progenitor_type = N/A
b-v = N/A
notes = is located 2.0" W and 0.4" N of the center of NGC 1260.

SN 2006gy was an extremely energetic supernova, sometimes referred to as a hypernova or Quark-nova [http://adsabs.harvard.edu/abs/2008AAS...212.6401L Superluminous Supernovae SN2006gy, SN2005gj and SN2005
] ] , that was discovered on September 18, 2006. It was first observed by Robert Quimby and P. Mondol,cite web | url = http://www.cfa.harvard.edu/iau/lists/Supernovae.html | title = List of Supernovae | accessdate = 2007-05-08] [http://astro.berkeley.edu/~bait/2006/sn2006gr.html IAU Circular No. 8754] , accessed May 8, 2007] and then studied by several teams of astronomers using facilities that included the Chandra, Lick, and Keck Observatories. [http://arxiv.org/abs/astro-ph/0612408v2 SN 2006gy: "An extremely luminous supernova in the galaxy NGC 1260"] Ofek et al., Accessed May 8 2007, arxiv.org] [http://arxiv.org/abs/astro-ph/0612617 Discovery of the most luminous supernova ever recorded, powered by the death of an extremely massive star like Eta Carinae] , Smith et al. ( [http://arxiv.org/pdf/astro-ph/0612617v3 PDF] )] 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". [http://www.nasa.gov/mission_pages/chandra/news/chandra_bright_supernova.html "NASA's Chandra Sees Brightest Supernova Ever"] , NASA Press Release on the Discovery, May 7, 2007] In October 2007 Quimby announced that SN 2005ap had broken SN 2006gy's record as the brightest ever recorded supernova. [ [http://space.newscientist.com/channel/astronomy/dn12778-enigmatic-supernova-smashes-brightness-record.html "Enigmatic supernova smashes brightness record"] , "New Scientist", October 12, 2007] Time magazine listed the discovery of SN 2006gy as third in its Top 10 Scientific Discoveries for 2007. [ [http://www.time.com/time/specials/2007/top10/article/0,30583,1686204_1686252_1690931,00.html "Top 10 Scientific Discoveries: #3. Brightest Supernova Recorded"] , "Time", 2007]

Characteristics

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 (M_⊙), possibly of a type referred to as a "pair-instability" supernova. The kinetic energy released by the explosion has been estimated at 10⁵² ergs (10⁴⁵ J) making it ten times more powerful than the typical supernova explosion which produces 10⁵¹ ergs (10⁴⁴ J) 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.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 was roughly comparable to the peak luminosity of the prior most luminous observed supernovae.] .

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 high energy gamma rays which have a greater energy than the rest mass of two electrons (mass-energy equivalence). These gamma rays interact with electromagnetic fields of the atomic nuclei in the star, and become particle and anti-particle pairs of electrons and positrons. This causes the average travel distance of the gamma rays to become shorter, causing the temperature of the interior of the star to rise. This causes an even larger fraction of the produced gamma rays to be of high enough energy for pair production, causing more of the energy to be reabsorbed closer to its source. This creates a runaway reaction. As the energy is concentrated more and more into the star's core, the outer layers start to fall inwards, which then compress the core. The compression and heating produce a rapid (few seconds) thermonuclear burn or explosion of the core material. The explosion blows the star completely apart without leaving a black hole remnant behind. [http://www.mpa-garching.mpg.de/~hammer/lager/pair.pdf Pair Instability Supernovae and Hypernovae] , Nicolay J. Hammer, 2003, accessed May 7, 2007]

Although the SN 2006gy supernova was intrinsically about one hundred 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.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 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 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, 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. cite web | last = | first =| date = 2007 | url = http://news.com.com/Megastar+explodes+in+brightest+supernova+ever+seen/2100-11397_3-6181997.html | title = Megastar explodes in brightest supernova ever seen| publisher = Reuters | language = English | accessdate = 2007-05-07 ]

References

External links

* [http://antwrp.gsfc.nasa.gov/apod/ap070510.html Astronomy Picture of the Day ] 10 May 2007
* [http://www.nasa.gov/mission_pages/chandra/news/chandra_bright_supernova.html NASA's Chandra Sees Brightest Supernova Ever]
* [http://www.ucolick.org/~alex/firststars/ Workshop on First Stars III website] (upcoming conference, links to prior papers)
* [http://www.cnn.com/2007/TECH/space/05/07/supernova/index.html Giant exploding star outshines previous supernovas (CNN.com)]
* [http://www.space.com/scienceastronomy/070507_brighest_sn.html Space.com article on SN 2006gy.]
* [http://news.bbc.co.uk/1/hi/sci/tech/6633609.stm "Star dies in brightest supernova"] , BBC, Tuesday, 8 May 2007, 03:35 GMT
* [http://www.time.com/time/magazine/article/0,9171,1619560,00.html The Greatest Show in Space, Time magazine Thursday, May 21st, 2007 Pages 56-57]
* [http://www.csmonitor.com/2007/0508/p01s04-usgn.html Supernova may offer new view of early universe]
* [http://mthamilton.ucolick.org/public/research/AO/ Lick Observatory Laser Guide Star Adaptive Optics]
* [http://pairitel.org PAIRITEL (telescope) website]
* [http://aladin.u-strasbg.fr/AladinPreview?-c=03+17+27.06%2B41+24+19.5&ident=SN+2006GY&submit=Aladin+previewer Image SN 2006gy]