Evidence of heavy-element ashes in thermonuclear X-ray bursts with photospheric superexpansion
Evidence of heavy-element ashes in thermonuclear X-ray bursts with photospheric superexpansion
A small subset of thermonuclear X-ray bursts on neutron stars exhibit such a strong photospheric expansion that for a few seconds the photosphere is located at a radius <i>r<i/><sub>ph<sub/> 10<sup>3<sup/> km. Such “superexpansions” imply a large and rapid energy release, a feature characteristic of pure He burst models. Previous calculations …