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arXiv 0909.1971astro-ph.COastro-ph.SR
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高浓度暗物质晕中年轻低质量恒星的形成和演化

The formation and evolution of young low-mass stars within halos with high concentration of dark matter particles

Jordi Casanellas, Ilidio Lopes

摘要:

低质量恒星在暗物质(DM)稠密晕中的形成和演化导致了与经典恒星演化截然不同的演化情景。由于我们详细的数值计算工作,我们描述了这些新的情况下,DM密度的范围内的主机晕,一系列的散射截面的DM粒子考虑,和恒星质量从0.7到3 M_{\odot}。首次,我们还计算了年轻的低质量恒星在前主序星阶段的Hayashi轨道的演化,发现对于高DM密度,这些恒星在到达主序星之前停止了引力坍缩,与第一颗恒星的类似研究一致。这样的恒星无限期地保持在一个平衡态,具有较低的有效温度(|ΔT_eff|> 10^3 K(对于一个太阳质量的恒星),被捕获的DM粒子在其核心的湮灭是唯一的能量来源。在DM密度较低的情况下,这些原恒星会继续坍缩,并以较低的速度通过主序燃烧氢。如果一颗M_{\odot}为1的恒星在密度为ρ_x =10^9 GeV cm^-3的晕中演化,那么它将花费比宇宙当前年龄更长的时间来消耗其核心中的所有氢。我们还显示了强烈的依赖性的有效温度和光度的这些恒星的DM粒子的特性,以及如何这可以被用来作为一种替代方法DM的研究。

英文摘要:

The formation and evolution of low-mass stars within dense halos of dark matter (DM) leads to evolution scenarios quite different from the classical stellar evolution. As a result of our detailed numerical work, we describe these new scenarios for a range of DM densities on the host halo, a range of scattering cross sections of the DM particles considered, and for stellar masses from 0.7 to 3 M_{\odot}. For the first time, we also computed the evolution of young low-mass stars in their Hayashi track in the pre-main sequence phase and found that, for high DM densities, these stars stop their gravitational collapse before reaching the main sequence, in agreement with similar studies on first stars. Such stars remain indefinitely in an equilibrium state with lower effective temperatures (|ΔT_eff| > 10^3 K for a star of one solar mass), the annihilation of captured DM particles in their core being the only source of energy. In the case of lower DM densities, these proto-stars continue their collapse and progress through the main sequence burning hydrogen at a lower rate. A star of 1 M_{\odot} will spend a time greater than the current age of the universe consuming all the hydrogen in its core if it evolves in a halo with DM density ρ_χ=10^9 GeV cm^-3. We also show the strong dependence of the effective temperature and luminosity of these stars on the characteristics of the DM particles and how this can be used as an alternative method for DM research.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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