Fusion of neutron rich oxygen isotopes in the crust of accreting neutron stars

dc.creatorHorowitz, C. J.
dc.creatorDussan, H.
dc.creatorBerry, D. K.
dc.date2007-10-30
dc.date2008-04-07
dc.date.accessioned2026-07-07T11:38:27Z
dc.date.available2026-07-07T11:38:27Z
dc.descriptionFusion reactions in the crust of an accreting neutron star are an important source of heat, and the depth at which these reactions occur is important for determining the temperature profile of the star. Fusion reactions depend strongly on the nuclear charge $Z$. Nuclei with $Z\le 6$ can fuse at low densities in a liquid ocean. However, nuclei with Z=8 or 10 may not burn until higher densities where the crust is solid and electron capture has made the nuclei neutron rich. We calculate the $S$ factor for fusion reactions of neutron rich nuclei including $^{24}$O + $^{24}$O and $^{28}$Ne + $^{28}$Ne. We use a simple barrier penetration model. The $S$ factor could be further enhanced by dynamical effects involving the neutron rich skin. This possible enhancement in $S$ should be studied in the laboratory with neutron rich radioactive beams. We model the structure of the crust with molecular dynamics simulations. We find that the crust of accreting neutron stars may contain micro-crystals or regions of phase separation. Nevertheless, the screening factors that we determine for the enhancement of the rate of thermonuclear reactions are insensitive to these features. Finally, we calculate the rate of thermonuclear $^{24}$O + $^{24}$O fusion and find that $^{24}$O should burn at densities near $10^{11}$ g/cm$^3$. The energy released from this and similar reactions may be important for the temperature profile of the star.
dc.description7 pages, 4 figs, minor changes, to be published in Phys. Rev. C
dc.identifierhttps://arxiv.org/abs/0710.5714
dc.identifierhttp://arxiv.org/abs/0710.5714
dc.identifierPhys.Rev.C77:045807,2008
dc.identifierdoi:10.1103/PhysRevC.77.045807
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/199567
dc.subjectAstrophysics
dc.subjectNuclear Theory
dc.titleFusion of neutron rich oxygen isotopes in the crust of accreting neutron stars
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