Bremsstrahlung emission from nucleon-nucleus reactions in dense medium of compact stars

Abstract Bremsstrahlung photons emitted during nucleon-nucleus reactions in compact stars are investigated. The influence of stellar medium density on emission intensity is studied from a quantum perspective for the first time. A bremsstrahlung model is generalized, where a new term describing the influence of the stellar medium is added to interactions between nucleons and nuclei (in the framework of a nuclear model of deformed oscillatoric shells). Polytropic EOS, Chandrasekar EOS, and Harrison-Wheeler EOS are employed for calculation. Haensel and Potekhin's unified EOS of neutron-star matter based on FPS and SLy EOSs are used for tests. Bremsstrahlung calculations are tested on existing measurements of bremsstrahlung in the scattering of protons off 197 Au nuclei at a proton beam energy of MeV. Many properties of bremsstrahlung emitted from nuclear processes in the stellar medium of compact stars are studied for the first time. In particular, the spectra of photons in the scattering of protons and neutrons off 4 He, 8 Be, 12 C, 16 O, 24 Mg, 40 Ca, 56 Fe are estimated based on stellar medium density. The medium of white dwarfs has a small influence on the bremsstrahlung emission from nuclear processes, while bremsstrahlung emission is intensive in neutron stars and it is changed in dependence on stellar medium and structure.