Hydrodynamic Thermonuclear Runaways in Superbursts

Abstract

We calculate the thermal and dynamical evolution of the surface layers of an accreting neutron star during the rise of a superburst. For the first few hours following unstable 12C ignition, the nuclear energy release is transported by convection. However, as the base temperature rises, the heating time becomes shorter than the eddy turnover time and convection becomes inefficient. This results in a hydrodynamic nuclear runaway, in which the heating time becomes shorter than the local dynamical time. Such hydrodynamic burning can drive shock waves into the surrounding layers and may be the trigger for the normal X-ray burst found to immediately precede the onset of the superburst in both cases where the Rossi X-Ray Timing Explorer was observing.

4 pages, 3 figures (emulateapj), accepted to ApJ Letters

References in corpus (12)

• A Remarkable Three Hour Thermonuclear Burst From 4U 1820-30
• Carbon Flashes in the Heavy Element Ocean on Accreting Neutron Stars
• Long Type I X-ray Bursts and Neutron Star Interior Physics
• Rotational Evolution During Type I X-Ray Bursts
• Exposing the Nuclear Burning Ashes of Radius Expansion Type I X-ray Bursts
• Evidence for a Millisecond Pulsar in 4U 1636-53 During a Superburst
• The Thermal Evolution following a Superburst on an Accreting Neutron Star
• The observers' view of (very) long X-ray bursts: they are super!
• Superburst Ignition and Implications for Neutron Star Interiors
• Thermonuclear X-ray Bursts: Theory vs. Observations
• Theoretical Models of Superbursts on Accreting Neutron Stars
• On the Production and Survival of Carbon Fuel for Superbursts on Accreting Neutron Stars: Implications for Mass Donor Evolution

Cited by in corpus (15)

• The Effects of Variations in Nuclear Processes on Type I X-Ray Burst Nucleosynthesis
• Thermonuclear X-ray bursts
• Nuclear Physics of the Outer Layers of Accreting Neutron Stars
• Evidence of heavy-element ashes in thermonuclear X-ray bursts with photospheric superexpansion
• Nuclear astrophysics: the unfinished quest for the origin of the elements
• Measurement of neutron star parameters: a review of methods for low-mass X-ray binaries
• The Impact of Uncertainties in Reaction Q-values on Nucleosynthesis in Type I X-Ray Bursts
• Multi-Zone Models of Superbursts from Accreting Neutron Stars
• Carbon Detonation and Shock-Triggered Helium Burning in Neutron Star Superbursts
• An unusual precursor burst with oscillations from SAX J1808.4-3658
• Generation of Type I X-ray Burst Oscillations by Unstable Surface Modes
• Dynamics of Laterally Propagating Flames in X-ray Bursts. I. Burning Front Structure
• Hydrodynamical simulation of detonations in superbursts. I. The hydrodynamical algorithm and some preliminary one-dimensional results
• A search for the $835\text{Hz}$ superburst oscillation signal in the regular thermonuclear bursts of 4U 1636-536
• Tracing the outburst decay of soft X-ray transients Aql X-1 and 4U 1608-52 with XSPECT