Carbon-enhanced metal-poor stars and thermohaline mixing
Carbon-enhanced metal-poor stars and thermohaline mixing
复制标题
碳增强贫金属恒星和温盐混合
DOI：
--
复制
发表时间：
2007
期刊：
影响因子：
--
通讯作者：
O. Pols
中科院分区：
文献类型：
--
作者：
R. Stancliffe;E. Glebbeek;R. Izzard;O. Pols
一种可能的形成碳增强贫金属恒星的情况是从一个可能不再可见的双星伴星吸积富碳物质。一般认为，吸积的物质留在星星的表面，直到第一次被清理出来才与内部混合。然而，温盐混合应该混合吸积物质与原始恒星物质，因为它具有较高的平均分子量。我们通过模拟一个金属丰度Z = 10−4的双星系统来研究这对表面丰度的影响，该双星系统具有一颗2 M的主星星星和一颗0.74 M的次级星星，初始轨道为4000天。吸积的物质从风的主要导致形成一个富含碳的secondary.We发现，吸积的材料混合相当迅速，整个星星的90%，与表面组成的重要后果。与热盐混合模型预测非常不同的表面丰度后，第一次疏浚相比，恒星演化的典型模型。
One possible scenario for the formation of carbon-enhanced metal-poor stars is the accretion of carbon-rich material from a binary companion which may no longer visible. It is generally assumed that the accreted material remains on the surface of the star and does not mix with the interior until first dredge-up. However, thermohaline mixing should mix the accreted material with the original stellar material as it has a higher mean molecular weight. We investigate the effect that this has on the surface abundances by modelling a binary system of metallicity Z = 10−4 with a 2 M primary star and a 0.74 M secondary star in an initial orbit of 4000 days. The accretion of material from the wind of the primary leads to the formation of a carbon-rich secondary.We find that the accreted material mixes fairly rapidly throughout 90% of the star, with important consequences for the surface composition. Models with thermohaline mixing predict very different surface abundances after first dredge-up compared to canonical models of stellar evolution.