On Collapsed Neutron Stars.

Abstract

Some consequences are discussed of the hypothesis that certain stars and cores of stars are composed mainly of neutrons. On the assumption that supernovae represent rapid transitions of ordinary stars into neutron stars, the large red shifts observed in the spectra of the recent bright supernovae are interpreted as gravitational red shifts. The neutron-star hypothesis, in conjunction with the general theory of relativity, leads to a theory of critical stellar masses. In view of the rapid advances made recently in the observation of supemovae, it seems appropriate to give here a brief summary of some conclusions of a series of theoretical investigations concerning the properties of highly collapsed neutron stars, which it is hoped may be ready for publication in the near future. The neutron-star hypothesis was first introduced by Baade and myself 1 in an effort to account for the tremendous liberation of energy in superno vae. We suggested the existence of stars and cores of stars the average density of which is comparable with the density of matter ordinarily encountered only inside of atomic nuclei. With the designation "neutron star" we do not wish to imply, however, that such a star is to be regarded as a giant nucleus composed of separate neutrons of precisely the same character as free neutrons. We only suggest, that, in contradistinction to ordinary stellar matter , in neutron stars already minute regions whose linear dimensions are larger than 8 = e^lmeC 2 = 2.8 X io-13 cm are electrically neutral. We here briefly describe some of the properties of neutron stars, as well as some new observations of supemovae which tend to support the neutron-star hypothesis. a) Cold neutron stars, according to present knowledge, represent states of lowest energy that matter may assume without being completely transformed into radiation.