14 research outputs found
Analytic solution for kinetic equilibrium of beta-processes in nucleonic plasma with relativistic pairs
The analytic solution is obtained describing kinetic equilibrium of the
-processes in the nucleonic plasma with relativistic pairs. The nucleons
are supposed to be non-relativistic and non-degenerate, while the
electrons and positrons are ultra-relativistic due to high temperature
K), or high density g/cm), or both, where
is a number of nucleons per one electron. The consideration is simplified
because of the analytic connection of the density with the electron chemical
potential in the ultra-relativistic plasma, and Gauss representation of Fermi
functions. Electron chemical potential and number of nucleons per one initial
electron are calculated as functions of and .Comment: 16 pages, 6 figure
Type Ia Supernova Explosion Models
Because calibrated light curves of Type Ia supernovae have become a major
tool to determine the local expansion rate of the Universe and also its
geometrical structure, considerable attention has been given to models of these
events over the past couple of years. There are good reasons to believe that
perhaps most Type Ia supernovae are the explosions of white dwarfs that have
approached the Chandrasekhar mass, M_ch ~ 1.39 M_sun, and are disrupted by
thermonuclear fusion of carbon and oxygen. However, the mechanism whereby such
accreting carbon-oxygen white dwarfs explode continues to be uncertain. Recent
progress in modeling Type Ia supernovae as well as several of the still open
questions are addressed in this review. Although the main emphasis will be on
studies of the explosion mechanism itself and on the related physical
processes, including the physics of turbulent nuclear combustion in degenerate
stars, we also discuss observational constraints.Comment: 38 pages, 4 figures, Annual Review of Astronomy and Astrophysics, in
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SN 1987A: Historical view about registration of the neutrino signal with Baksan, KAMIOKANDE II and IMB detectors
The detection of neutrinos from SN 1987A opened a new era in neutrino astrophysics in the last century. We present a historical view about registration of the neutrino signal from supernova SN 1987A in the Large Magellanic Cloud by the BAKSAN liquid scintillator detector and by the two water Cherenkov detectors — Kamiokande-II and IMB. All three detectors observed a total neutrino signal of 24 events at 7:35 UT 23 February, 1987. I will concentrate mostly about the BAKSAN supernova group analysis of the neutrino signal, which was already done in the years 1987 and 1988. The results of this analysis (determination of average properties of the neutrino signal: the total energy of neutrino emission, the effective neutrino temperature, the total luminosity of the neutrino signal, duration of the neutrino burst) are presented. The common analysis of all three detectors shows that these 'parameters' have good agreement with the general theoretical description of explosions of supernovae. The analysis shows that the inclusion of the BAKSAN data is very important for the understanding of the SN87A event. The latest results of 20 years of observation of our Galaxy by the BAKSAN scintillation telescope show that the upper limit of the mean frequency of gravitational collapses is <0.13 yr^-1 at a 90% confidence level