Gamma bursts from neutron stars and stellar flares

If gamma bursts are locally galactic, then the implied fluxes from a localized region of a neutron star surface are closed to the blackbody limit even at the extreme temperatures (of the order of 109 degrees) inferred from gamma‐burst spectra. One reasonable model is the accretion of an astroid or comet (Harwit and Salpeter 1973) onto a magnetized neutron star. What is frequently described as tidal disruption, instead becomes gravitational compression. Matter landing on a neutron star releases a specific energy density of several times c2/10. This energy density is ample to give rise to the inferred temperatures of 108 to 109 degrees. However, radiation stress greatly exceeds the gravitational stress even at the neutron star surface and a near instantaneous adiabatic expansion of the hot surface layers, cools them, and terminates the release of any high temperature radiation. The effective temperature of the radiation then becomes roughly the Eddington limit of 2×107 degrees. Only by the restraint of the ...