Carbon production on accreting neutron stars in a new regime of stable nuclear burning

摘要: Accreting neutron stars exhibit Type I X-ray bursts from both frequent hydrogen/helium flashes as well rare carbon flashes. The latter (superbursts) ignite in the ashes of former. Hydrogen/helium bursts, however, are thought to produce insufficient power superbursts. Stable burning could create required carbon, but this was predicted only occur at much larger accretion rates than where superbursts observed. We present models a new steady-state regime stable hydrogen and helium that produces pure ashes. Hot CNO heats star envelope causes burn before conditions flash reached. This takes place when mass rate is around 10% Eddington limit: close most occur. find increased heating base sustains by steepening temperature profile, which increases amount burns runaway can ensue.