SN 2006gy

SN 2006gy is a supernova that was discovered (by Nathan Smith University of Berkeley, California, team ) on 18 September 2006 as part of the Texas Supernova Search program. It is located in the galaxy NGC 1260, which is about 73 Mpc ( about 238 million light years) is removed, and is currently classified as a supernova type IIb due to weak hydrogen lines.

SN 2006gy, however, differs significantly from other supernovae: The previously known supernovae have absolute magnitudes of about -16 to -20.5 mag on (mag ), the most luminous reached its maximum about 20 days after discovery - SN 2006gy is, however, a luminosity of -22 likes by more than a magnitude more luminous and thus, based on the absolute brightness (mag M = -22.7 ) at that time according to SN 2005ap second brightest known supernova; Moreover, the brightness was about 100 days over -21 mag and the maximum was not reached until 70 days after the discovery.

Possible explosion mechanisms

The mechanism behind the explosion, however, is not yet clarified. The following theories are being discussed:

Extremely massive progenitor star

The progenitor star can only be a very massive star after interpretation of the discovering team: After yet plausible scenario in which much of the luminosity from the decay of 56Ni ( decay chain: 56Ni → 56Co → 56Fe ) comes from, about 20 solar masses would be the order of magnitude required to 56Ni ( the mechanism of fusion reactions see nucleosynthesis ); typical amounts of nickel are, however, in the case of a supernova of type II and a stellar mass 15-20 solar masses at about 0.07 solar masses, and thus by more than two orders of magnitude among them - that the progenitor star must have been much more difficult.

Pair instability supernova

Furthermore, the discovery team speaks of the possibility it might be variable ( LBV) η Car have acted similarly in the progenitor star is a luminous Strengthening Blue, which was completely torn apart by a pair instability. Although this hypothesis seems to fit very well to the known data of the supernova, so it contradicts several popular ideas of modern astrophysics:

• Although triggered by pair instability supernovae ( PISN ) since the 1980s, the subject of theoretical studies, but they are kept only in the early phase of the universe in the first generation of stars at a redshift of z = 15 to z = 30 possible: for a PISN is according to current model calculations, a helium nucleus 64-133 solar masses required, corresponding to a mass of the progenitor star of about 140 to 260 solar masses ( excluding the mass loss ) - only in the early phase of the universe you hold such massive stars possible, which is why there is no theoretical studies on a are possible pair instability in solar metallicity stars.
• Since it is light Strengthening Blue Variables is very massive stars that have not yet shed its hydrogen envelope, they are considered as precursors of the Wolf -Rayet stars and not as a direct precursor of a supernova - but also show more supernovae of Type IIn Notes to a LBV precursor.

Quark -Nova

Another possible scenario is a two-stage collapse was first proposed in a neutron star into a quark star and then by Denis Leahy and Rachid Ouyed from the University of Calgary. According to this hypothesis, is released in the formation of the quark star and the associated transformation of matter into strange matter enough energy to produce a second, faster shock wave from the outer layers of the neutron star, which collides with the Super Nova first exfoliated layers and thus produces the immense luminosity of this supernova. The Theory of Quark -Nova is so far controversial among experts.