Supernova Calculations and the Hot Bubble
The recent calculations of James Wilson and Ronald Mayle (1989) showed that the mechanism of supernova explosions caused by collapse to a neutron star now appears to be both, understood conceptually and modeled convincingly up to 3.4 s following collapse. In particular they show the formation of a hot, high entropy bubble that continues to push on the shocked matter for a time long enough that the subsequent history is not in significant doubt. The hot bubble is formed primarily due to mu, tau neutrino antineutrino annihilation as first proposed by Goodman, Dar, and Nussinov (1987). The hot bubble that separates the neutron star from the ejected matter has high entropy, 102 to 104, measured in units of the Boltzmann constant, k per free nucleon. This high entropy means that for every nucleon there axe many photons and electrons (pairs) and so the molecular weight is small and the scale height is large even at modest temperatures, ≤ 1MeV. Such a photon gas can “push” simultaneously on both the neutron star surface as well as on the expanding matter. It extends to a radius of 109 cm so that no fallback or reimplosion of any significant fraction of the ejected matter will take place. The kinetic and internal energy minus the gravitational energy of matter whose total energy is positive is 0.35 x 1051 ergs at 3.4 s. They expect this to increase to 1 to 1.5 x 1051 ergs by the end of the calculation, typical of Type II supernova.
KeywordsEntropy Helium Dition Nism Colgate
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