Model Atmospheres and X-Ray Spectra of Bursting Neutron Stars: Hydrogen-Helium Comptonized Spectra
Model Atmospheres and X-Ray Spectra of Bursting Neutron Stars: Hydrogen-Helium Comptonized Spectra
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DOI：
10.1051/0004-6361:20034048
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发表时间：
1991-07
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影响因子：
--
通讯作者：
J. Madej
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文献类型：
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作者：
J. Madej
康普顿散射在确定X射线爆发的大气结构及其理论谱中起着至关重要的作用。本文描述了一颗极热中子星星的平面平行模型大气及其理论出射辐射通量谱。我们的模型方程考虑到所有的束缚自由和自由自由的单色不透明度有关的氢氦化学成分，并考虑到康普顿散射的影响，在热等离子体中的辐射与完全相对论的热速度。我们使用康普顿散射项的转移方程，它精确地描述光子-电子的能量和动量交换的光子与初始能量超过电子静止质量的511千电子伏。用变爱丁顿因子技术求解模式大气方程。H-He模型大气和通量谱的网格是在107 K ≤ Teff ≤ 3 × 107 K的稠密网格上计算的，表面重力为log g。在许多情况下，假定测井曲线g接近临界重力测井曲线gcr，即，爱丁顿极限我们证实了X射线爆发的H-He谱偏离黑体谱，并讨论了它们的形状。色-有效温度比表表明，在流体静力平衡和辐射平衡的H-He大气中，Tc/Teff的理论值不超过1.9。
Compton scattering plays a crucial role in determining the structure of the atmosphere of an X-ray burster and its theoretical spectrum. Our paper presents a description of the plane-parallel model atmosphere of a very hot neutron star and its theoretical flux spectrum of outgoing radiation. Our model equations take into account all bound-free and free-free monochromatic opacities relevant to hydrogen-helium chemical composition and take into account the effects of Compton scattering of radiation in thermal plasma with fully relativistic thermal velocities. We use Compton scattering terms in the equation of transfer, which precisely describe photon-electron energy and momentum exchange for photons with initial energies exceeding the electron rest mass of 511 keV. Model atmosphere equations are solved with the variable Eddington factors technique. The grid of H-He model atmospheres and flux spectra is computed on a dense mesh of 107 K ≤ Teff ≤ 3 × 107 K and a surface gravity of log g. In many cases, the assumed log g approached the critical gravity log gcr, i.e., the Eddington limit. We confirm that H-He spectra of X-ray bursters deviate from blackbody spectra and discuss their shapes. The table of color to effective temperature ratios shows that theoretical values of Tc/Teff do not exceed 1.9 in H-He atmospheres in hydrostatic and radiative equilibrium.