L D Landau and the concept of neutron stars
a Ioffe Institute, ul. Polytekhnicheskaya 26, St. Petersburg, 194021, Russian Federation
b Nicolaus Copernicus Astronomical Center, Bartycka 18, Warsaw, 00-716, Poland
c Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL, USA
d Niels Bohr International Academy, Niels Bohr Institute, Blegdamsvej 17, Copenhagen, DK-2100, Denmark
e NORDITA, Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, Stockholm, SE-10691, Sweden
We review L Landau’s role in the history of neutron star physics in the 1930s. According to recollections of Rosenfeld (Proc. 16th Solvay Conference on Physics, 1974, p. 174), Landau improvised the concept of neutron stars in a discussion with Bohr and Rosenfeld just after the news of the discovery of the neutron reached Copenhagen in February 1932. We present arguments that the discussion must have taken place in March 1931, before the discovery of the neutron, and that they in fact discussed the paper written by Landau in Zurich in February 1931 but not published until February 1932 (Phys. Z. Sowjetunion 1 285). In this paper Landau mentioned the possible existence of dense stars which look like one giant nucleus; this could be regarded as an early theoretical prediction or anticipation of neutron stars, however, prior to the discovery of the neutron. The coincidence of the dates of the neutron’s discovery and the paper’s publication has led to an erroneous association of Landau’s paper with the discovery of the neutron. In passing, we outline the contribution of Landau to the theory of white dwarfs and to the hypothesis of stars with neutron cores.