Nuclear Reactions in the Crusts of Accreting Neutron Stars
| Autor: | Leandro Gasques, R. Lau, A. V. Afanasjev, Alex Deibel, Hendrik Schatz, P. Möller, S. S. Gupta, M. Beard, Michael Wiescher, William Raphael Hix, Andrew W. Steiner, Laurens Keek, Y. Xu, Edward F. Brown, Peter Shternin, G. W. Hitt |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Nuclear reaction
Nuclear Theory Astrophysics::High Energy Astrophysical Phenomena Non-equilibrium thermodynamics FOS: Physical sciences Astrophysics 01 natural sciences 7. Clean energy Physics::Geophysics Nuclear Theory (nucl-th) Nucleosynthesis Impurity 0103 physical sciences Nuclear Experiment 010306 general physics 010303 astronomy & astrophysics Solar and Stellar Astrophysics (astro-ph.SR) Physics High Energy Astrophysical Phenomena (astro-ph.HE) Range (particle radiation) Accretion (meteorology) Astronomy and Astrophysics Crust Neutron star Astrophysics - Solar and Stellar Astrophysics 13. Climate action Space and Planetary Science Astrophysics::Earth and Planetary Astrophysics Astrophysics - High Energy Astrophysical Phenomena |
| Zdroj: | NASA Astrophysics Data System |
| DOI: | 10.48550/arxiv.1803.03818 |
| Popis: | X-ray observations of transiently accreting neutron stars during quiescence provide information about the structure of neutron star crusts and the properties of dense matter. Interpretation of the observational data requires an understanding of the nuclear reactions that heat and cool the crust during accretion, and define its nonequilibrium composition. We identify here in detail the typical nuclear reaction sequences down to a depth in the inner crust where the mass density is 2E12 g/cm^3 using a full nuclear reaction network for a range of initial compositions. The reaction sequences differ substantially from previous work. We find a robust reduction of crust impurity at the transition to the inner crust regardless of initial composition, though shell effects can delay the formation of a pure crust somewhat to densities beyond 2E12 g/cm^3. This naturally explains the small inner crust impurity inferred from observations of a broad range of systems. The exception are initial compositions with A >= 102 nuclei, where the inner crust remains impure with an impurity parameter of Qimp~20 due to the N = 82 shell closure. In agreement with previous work we find that nuclear heating is relatively robust and independent of initial composition, while cooling via nuclear Urca cycles in the outer crust depends strongly on initial composition. This work forms a basis for future studies of the sensitivity of crust models to nuclear physics and provides profiles of composition for realistic crust models. 25 Pages, accepted for publication in Ap. J |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|