Lateral propagation of the helium shell flash on an accreting neutron star

Abstract

view Abstract Citations (31) References (9) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Lateral propagation of the helium shell flash on an accreting neutron star Nozakura, T. ; Ikeuchi, S. ; Fujimoto, M. Y. Abstract The propagation of a thermal wave caused by a helium flash on an accreting neutron star is investigated by a one-zone model. Our model consists of equations for the energy balance and the mass balance. The energy equation includes the nuclear reaction, the radial heat flux which is characterized by a parameter representing the temperature of the hydrogen burning zone, and the lateral heat flux. Another parameter of the model is the accretion rate in the mass equation. As for the lateral heat flux, two limiting cases are examined: one is the case that there is no convention, and the other is the case that the convection is effective for the lateral heat transport. The velocities of thermal waves are obtained in the above two cases for various parameters started from the local ignition of flashes. In the "convective case" the velocities are generally two orders of magnitude larger than those in the "conductive case," and the travel time across a large fraction of the surface of a neutron star is ∼ 0.1-10 s, depending upon the temperature of the hydrogen burning zone. Furthermore, if the initial surface density is inhomogeneous, there can be several interesting temperature profiles. The velocities of the waves are determined by the local pressure in these cases, and the waves never stop as long as the local pressure is beyond a certain critical value. Publication: The Astrophysical Journal Pub Date: November 1984 DOI: 10.1086/162590 Bibcode: 1984ApJ...286..221N Keywords: Computational Astrophysics; Helium; Neutron Stars; Stellar Mass Accretion; Stellar Structure; X Ray Sources; Computerized Simulation; Heat Balance; Heat Flux; Mass Balance; Propagation Velocity; Stellar Models; Thermal Radiation; Thermonuclear Reactions; Astrophysics full text sources ADS |