Astron. Astrophys. 330, 569-577 (1998)

Properties of dense matter in a supernova core
in the relativistic mean-field theory

Z.G. Dai ^{1, 2} and K.S. Cheng <sup>2

1</sup> Department of Astronomy, Nanjing University, Nanjing 210093, P.R. China (zgdai@netra.nju.edu.cn)
² Department of Physics, University of Hong Kong, Hong Kong (hrspksc@hkucc.hku.hk)

Received 12 November 1996 / Accepted 25 August 1997

Abstract

We have used the Zimanyi & Moszkowski model in the relativistic mean-field theory to study the properties of asymmetric nuclear matter and the equation of state (EOS) for supernova matter. We find that even though muons are included in the chemical composition of neutron-star matter, this model still results in a small proton concentration so that only the modified Urca process occurs as a main neutrino reaction in neutron stars. This conclusion is opposite to that of the previous studies in the relativistic mean-field theory. The incompressibility of symmetric nuclear matter is consistent with both the experimental values extracted from the nuclear physics and the constraints placed on the EOS by observations of neutron star masses. If the EOS for supernova matter is described by this model, the prompt mechanism for Type II supervovae cannot work, but the EOS is likely to be favourable to the delayed explosion mechanism.

Key words: dense matter relativity stars: supernovae: general stars: neutron

Send offprint requests to: K.S. Cheng

© European Southern Observatory (ESO) 1998

Online publication: January 16, 1998
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