Gamma ray heating rates due to chromium isotopes in stellar core during late stages of high mass stars (>10M_⊙)

GIK Institute of Engineering Sciences and Technology, Topi 23640, Khyber Pakhtunkhwa, Pakistan

Published online: 29 September 2017

Abstract

Gamma ray heating rates are thought to play a crucial role during the pre-supernova stage of high mass stars. Gamma ray heating rates, due to β^±-decay and electron (positron) capture on chromium isotopes, are calculated using proton-neutron quasiparticle random phase approximation theory. The electron capture significantly affects the lepton fraction (Y_e) and accelerates the core contraction. The gamma rays emitted as a result of weak processes heat the core and tend to hinder the cooling and contraction due to electron capture and neutrino emission. The emitted gamma rays tend to produce enormous entropy and set the convection to play its role at this stage. The gamma heating rates, on ^50-60Cr, are calculated for the density range 10 < ρ (g.cm^-3) < 10¹¹ and temperature range 10⁷ < T (K) < 3.0×10¹⁰.