New class of compact stars: Pion stars
B. B. Brandt (Institute for Theoretical Physics, Goethe Universität Frankfurt, D-60438 Frankfurt am Main, Germany); G. Endrődi (Institute for Theoretical Physics, Goethe Universität Frankfurt, D-60438 Frankfurt am Main, Germany); E. S. Fraga (Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21941-972, Rio de Janeiro, RJ, Brazil); M. Hippert (Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21941-972, Rio de Janeiro, RJ, Brazil, Instituto de Física, Universidade de São Paulo, Rua do Matão, Caixa Postal 1371, Butantã, CEP 05508-090, São Paulo, SP, Brazil); J. Schaffner-Bielich (Institute for Theoretical Physics, Goethe Universität Frankfurt, D-60438 Frankfurt am Main, Germany); et al - Show all 6 authors
We investigate the viability of a new type of compact star whose main constituent is a Bose-Einstein condensate of charged pions. Several different setups are considered, where a gas of charged leptons and neutrinos is also present. The pionic equation of state is obtained from lattice QCD simulations in the presence of an isospin chemical potential and requires no modeling of the nuclear force. The gravitationally bound configurations of these systems are found by solving the Tolman-Oppenheimer-Volkoff equations. We discuss weak decays within the pion condensed phase and elaborate on the generation mechanism of such objects.
