Crucial role of neutron diffusion in the crust of accreting neutron stars

ABSTRACT Observed temperatures of transiently accreting neutron stars in the quiescent state are generally believed to be supported by deep crustal heating, associated with non-equilibrium exothermic reactions in the crust. Traditionally, these reactions are studied by considering nuclear evolution...

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Bibliographic Details
Published in:Monthly notices of the Royal Astronomical Society. Letters 2020-06, Vol.495 (1), p.L32-L36
Main Authors: Chugunov, A I, Shchechilin, N N
Format: Article
Language:English
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Summary:ABSTRACT Observed temperatures of transiently accreting neutron stars in the quiescent state are generally believed to be supported by deep crustal heating, associated with non-equilibrium exothermic reactions in the crust. Traditionally, these reactions are studied by considering nuclear evolution governed by compression of the accreted matter. Here, we show that this approach has a basic weakness; that is, in some regions of the inner crust the conservative forces, applied for matter components (nuclei and neutrons), are not in mechanical equilibrium. In principle, the force balance can be restored by dissipative forces; however, the required diffusion fluxes are of the same order as total baryon flux at Eddington accretion. We argue that redistribution of neutrons in the inner crust should be involved in realistic model of accreted crust.
ISSN:1745-3925
1745-3933
DOI:10.1093/mnrasl/slaa055