Nuclear heating and melted layers in the inner crust of an accreting neutron star

Details Nuclear heating and melted layers in the inner crust of an accreting neutron star Nuclear heating and melted layers in the inner crust of an accreting neutron star

1999-10-12

arxiv.org/abs/astro-ph/9910215v1

Astronomy and Astrophysics

Astrophysics

36 pages, 14 figures, uses aastex version 5.0. Accepted for publication in ApJ

Scientific paper

10.1086/308487

A neutron star in a long-lived, low-mass binary can easily accrete enough matter to replace its entire crust. Previous authors noted that an accreted crust, being formed from the burning of accreted hydrogen and helium, allows a series of non-equilibrium reactions, at densities >6e11 g/cc, which release a substantial amount of heat (1 MeV per accreted nucleon). Recent calculations by Schatz et al. showed that the crystalline lattice of an accreted crust is also likely to be quite impure. This paper discusses the thermal structure of such a neutron star and surveys how the crust reactions and impurities affect the crust temperature. During accretion rapid enough to make the accreted hydrogen and helium burn stably (near the Eddington accretion rate; typical of the brightest low-mass neutron star binaries), most of the heat released in the crust is conducted into the core, where neutrino emission regulates the temperature. As a result there is an inversion of the thermal gradient: the temperature decreases with depth in the inner crust. The thermal structure in the crust at these high accretion rates is insensitive to the temperature in the hydrogen/helium burning shell. When the crust is very impure, the temperature can reach approximately 8e8 K at densities > 6e11 g/cc. This peak temperature depends mostly on the amount of heat released and the thermal conductivity and in particular is roughly independent of the core temperature. The high crust temperatures are sufficient to melt the crystalline lattice in thin layers where electron captures have substantially reduced the nuclear charge.

Affiliated with

Also associated with

No associations

Rating

Nuclear heating and melted layers in the inner crust of an accreting neutron star does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Nuclear heating and melted layers in the inner crust of an accreting neutron star, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Nuclear heating and melted layers in the inner crust of an accreting neutron star will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-446127