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首页> 外文期刊>The Astrophysical journal >NEW COOLING SEQUENCES FOR OLD WHITE DWARFS
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NEW COOLING SEQUENCES FOR OLD WHITE DWARFS

机译:旧的白矮星的新冷却顺序

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We present full evolutionary calculations appropriate for the study of hydrogen-rich DA white dwarfs. This is done by evolving white dwarf progenitors from the zero-age main sequence, through the core hydrogen-burning phase, the helium-burning phase, and the thermally pulsing asymptotic giant branch phase to the white dwarf stage. Complete evolutionary sequences are computed for a wide range of stellar masses and for two different metallicities, Z = 0.01, which is representative of the solar neighborhood, and Z = 0.001, which is appropriate for the study of old stellar systems, like globular clusters. During the white dwarf cooling stage, we self-consistently compute the phase in which nuclear reactions are still important, the diffusive evolution of the elements in the outer layers and, finally, we also take into account all the relevant energy sources in the deep interior of the white dwarf, such as the release of latent heat and the release of gravitational energy due to carbon-oxygen phase separation upon crystallization. We also provide colors and magnitudes for these sequences, based on a new set of improved non-gray white dwarf model atmospheres, which include the most up-to-date physical inputs like the Lyα quasi-molecular opacity. The calculations are extended down to an effective temperature of 2500 K. Our calculations provide a homogeneous set of evolutionary cooling tracks appropriate for mass and age determinations of old DA white dwarfs and for white dwarf cosmochronology of the different Galactic populations.
机译:我们提供适合研究富氢DA白矮星的完整进化计算。这是通过使白矮星祖先从零年龄主序列演化到核心的氢燃烧相,氦燃烧相和热脉冲渐近巨分支相发展到白矮星阶段来实现的。对于广泛的恒星质量和两种不同的金属度,计算出完整的演化序列,Z = 0.01(代表太阳邻域)和Z = 0.001(适合于研究旧的恒星系统,如球状星团)。在白矮星冷却阶段,我们始终如一地计算核反应仍然重要的阶段,外层元素的扩散演化,最后,我们还考虑了深部内部的所有相关能源白矮星的形变,例如由于结晶时碳氧相分离而释放的潜热和释放的重力能量。我们还基于一组新的改进的非灰色白矮星模型大气,为这些序列提供了颜色和大小,其中包括最新的物理输入,如Lyα准分子不透明性。计算被扩展到有效温度2500K。我们的计算提供了一组均匀的演化冷却径迹,适用于确定老DA白矮星的质量和年龄以及不同银河种群的白矮星年代学。

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