| Partially Ionized Layers of Accreted Envelopes of Weakly and Strongly Magnetized Neutron Stars (2007) | |||||||||||||
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| . We study equilibrium properties of partially ionized hydrogen atmospheres and subphotospheric layers of weakly (with magnetic eld B 10 9 G) and strongly (B 10 10 G) magnetized neutron stars. In both weak- and strong-eld cases, the ionization degree, atomic occupation numbers, and equation of state are calculated. These results are used to calculate opacities of neutron-star atmospheres. Our study is aimed at construction of reliable atmosphere models and interpretation of the soft X-ray thermal emission of neutron stars with hydrogen atmospheres. Partial ionization, which occurs at temperature T < 10 5 K in the weak eld and at T < 10 6:5 K in the strong eld, aects the equation of state (EOS) and opacities. We study these eects using the \chemical picture" of the plasma (e.g., Saumon, Chabrier, & Van Horn 1995). At B = 0, we nd a good agreement with the OPAL data (Iglesias & Rogers 1996). The motion of charged particles in a magnetic eld is quantized into... | |||||||||||||
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