论文标题
Omega Centauri金属富红色巨人的氦气增强
Helium Enhancement in the Metal Rich Red Giants of Omega Centauri
论文作者
论文摘要
由Hema和Pandey富含氦气的（富含氦气的）金属富含金属的红色巨人，使用了Vainu Bappu望远镜（VBT）的低分辨率光谱（VBT）发现，并通过从HRS-SUST-SUST SUST AFRIAMAN大型telescope（sall）中获得的高分辨率分析（vainu bappu望远镜（VBT）确认，并得到了392的高分辨率频谱（for）。在这里重新纳入以确定其增强/氢有缺陷的程度（H缺乏症）。观察到的MGH带与具有不同HE/H比的模型大气相结合用于分析。这两个巨人的HE/H比是通过强制执行以下事实确定的：从MGI线中衍生的Mg丰度，而从MGH频段的下属线中必须相同。 LEID 34225和LEID 39048的估计HE/H比分别为0.15 +/- 0.04和0.20 +/- 0.04，而正常HE/H比为0.10。遵循对其他两个比较恒星的分析（LEID 61067和LEID 32169）的相同标准，获得了0.10的正常HE/H比。 0.15-0.20的HE/H比对应于大约0.375-0.445的氦（Z（HE）= Y）的质量分数。氦气增强的范围和程序恒星的衍生金属性均与针对欧米茄蓝色主序列恒星确定的范围一致。因此，我们的研究为欧米茄Centuari的金属富含氦增强的人群的进化轨迹提供了缺失的联系。这项研究工作是使用MGI和MGH线的金属富含红色巨型欧米茄巨人的HE-ENHASEMENT量的第一光谱测定。
The helium-enriched (He-enriched) metal-rich red giants of Omega Centauri, discovered by Hema and Pandey using the low-resolution spectra from the Vainu Bappu Telescope (VBT) and confirmed by the analyses of the high-resolution spectra obtained from the HRS-South African Large Telescope (SALT) for LEID 34225 and LEID 39048, are reanalysed here to determine their degree of He-enhancement/hydrogen-deficiency (H-deficiency). The observed MgH band combined with model atmospheres with differing He/H ratios are used for the analyses. The He/H ratios of these two giants are determined by enforcing the fact that the derived Mg abundances from the MgI lines and from the subordinate lines of the MgH band must be same for the adopted model atmosphere. The estimated He/H ratios for LEID 34225 and LEID 39048 are 0.15+/-0.04 and 0.20+/-0.04, respectively, whereas the normal He/H ratio is 0.10. Following the same criteria for the analyses of the other two comparison stars (LEID 61067 and LEID 32169), a normal He/H ratio of 0.10 is obtained. The He/H ratio of 0.15-0.20 corresponds to a mass fraction of helium (Z(He)=Y) of about 0.375-0.445. The range of helium enhancement and the derived metallicity of the program stars are in line with those determined for Omega Cen blue main-sequence stars. Hence, our study provides the missing link for the evolutionary track of the metal-rich helium-enhanced population of Omega Centuari. This research work is the very first spectroscopic determination of the amount of He-enhancement in the metal-rich red giants of Omega Centauri using the MgI and MgH lines.
