In response to the proposed high-helium content stars as an explanation for the double main sequence observed in ω Centauri, we investigated the consequences of such stars elsewhere on the color-magnitude diagram. We concentrated on the horizontal branch, where the effects of high helium are expected to show themselves more clearly. In the process we developed a procedure for comparing the mass loss suffered by differing stellar populations in a physically motivated manner. High-helium stars in the numbers proposed seem absent from the horizontal branch of ω Cen unless their mass-loss history is very different from that of the majority metal-poor stars. It is possible to generate a double main sequence with existing ω Cen stars via accretion of helium-rich pollution consistent with the latest AGB ejecta theoretical yields and such polluted stars are consistent with the observed HB morphology of ω Cen. Polluted models are consistent with observed merging of the main sequences as opposed to our models of helium-rich stars. Using the (B - R)/(B + V + R) statistic, we find that the high-helium bMS stars require an age difference compared to the rMS stars that is too great, whereas the pollution scenario stars have no such conflict for inferred ω Cen mass losses.
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机译:作为对拟议的高氦含量恒星的解释,它是对在ωCentauri中观测到的双主序列的解释,我们在色度图上调查了其他恒星的后果。我们集中在水平分支上,在该分支上,高氦的影响有望更加明显。在此过程中,我们开发了一种程序,用于以物理方式比较不同恒星群体遭受的质量损失。拟议数量的高氦恒星似乎不在ωCen的水平分支中出现,除非它们的质量损失历史与大多数贫金属恒星的质量损失历史非常不同。通过与最新的AGB喷射理论产率一致的富氦污染的积累,可以用现有的ωCen星生成双主序列,而这种污染的星与观测到的ωCen HB形态一致。与我们的富氦恒星模型相反,受污染的模型与观察到的主要序列合并一致。使用(B-R)/(B + V + R)统计量,我们发现高氦bMS恒星与rMS恒星相比需要年龄差异太大,而污染情景中的恒星没有这种冲突推断ωCen质量损失。
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