ar X iv : a st ro - p h / 04 01 37 1 v 1 1 9 Ja n 20 04 DYNAMIC STABILITY OF COMPACT STARS
نویسنده
چکیده
After some historical remarks we discuss different criteria of dynamical stability of stars, and properties of the critical states where dynamical stability is lost, leading to collapse with formation of the neutron star or a black hole. At the end some observational and theoretical problems related to quark stars are discussed. 1. Introduction It was first noted by S Chandrasekhar in 1931 that the mass of the compact star at very large densities, when electrons become relativis-tically degenerate cannot exceed a value, which is now called as Chan-drasekhar limit for white dwarfs (Chandrasekhar, 1931). After discovery of the neutron in 1932 the idea of the neutron star existence was developed. The matter in these stars is so dense, that neutrons become relativistically degenerate, again leading to the maximum mass of the neutron star. There are two important differences between white dwarfs and neutron stars, influencing the stability and mass limit. Neutron stars are about 6 orders of magnitude denser, than white dwarfs, making necessary to use general relativity (GR) in description of gravitation, instead of newtonian gravity. In GR the gravitation force is growing faster than 1/r 2 , what reduce a stability and decrease the mass limit. On the other hand neutrons interaction become important at densities exceeding the nuclear one. The repulsion forces between nucleons at large densities * Partial funding provided by RFBR grant 02-02-16900.
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