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Q. Peng (Department of Astronomy, Nanjing University)
The explosion mechanism of the SNII is a puzzle and still remains an open question up to date. In this paper, we propose a new explosion mechanism of SNII based on a new criterion for the SN collapse condition. The detail of the work is discussed in following steps: a) We choose the condition that the timescale of the electron capture being shorter than that of the hydrodynamic collapsing as a new criterion to initiate the fast collapse of a SN core, as a replacement of the well recognized Chandrasekhar mass limit criterion. With this new criterion, we demonstrate that the rapid collapsing core of the SNII is only a part of an iron core, instead of being the whole iron core of the presupernova. b) We illustrate that a rapid collapsing core under such condition can supply a prompt explosion mechanism for the SNII. Both an outgoing rebounded shock wave and a neutrino flux produced in the nascence neutron star can travel through the rapid collapsing core during the collapsing process. c) We further demonstrate the presence of a high temperature vacuum zone between the rapid collapsing inner core and the outer slowly contracting iron core of the presupernova in this two-core model. The density in the vacuum zone is much lower than that in both inner and out cores. In this region, both the radiation field and the neutrino flux go through an expansion approximately as T4\times R3 ~const. . The temperatures of both the radiation field in the outgoing shock wave and the neutrino flux continue to decrease until the energy of the gamma ray photons in the outgoing shock wave and that of the neutrino in the neutrino flux drop below the bonding energy of a nucleon for iron group nucleus. The nuclei in the rest slowly contracting iron core of the presupernova will not be disintegrated by both the gamma ray photons in the outgoing shock wave and the neutrino in the neutrino flux. d) We finally show that, under this mechanism, the rest slowly contracting outer iron core, the mantle and the atmosphere of the presupernova are eventually blown out by the radiation pressure of the outgoing shock wave and the neutrino flux through the interaction between the neutrinos and the iron group nuclei. This is just the supernova explosion.
The author(s) of this abstract have provided an email address for comments about the abstract: qhpeng@nju.edu.cn
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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.