In this work, the helium-enhancement (He-enhancement) in the lithium-rich (Li-rich) K-giant HD 77361 is investigated using the strengths of the MgH band and the Mg i lines. The detailed abundance analysis and also the synthesis of the MgH band and the Mg i lines has been carried out for HD 77361. One would expect, within uncertainities, same Mg abundance from both the MgH and Mg i lines. But, we found that Mg abundance derived from MgH lines is significantly less than the abundance from Mg i lines, and this difference cannot be reconciled by changing the stellar parameters within the uncertainties, implying He enhancement in star’s photosphere. The He enhancement in the atmospheres is estimated by using models of different He/H ratios so that both the lines, MgH as well as Mg i , return the same Mg abundance for the adopted model’s He/H ratio. We found $$\mathrm{He/H}=0.4\pm 0.1$$ He / H = 0.4 ± 0.1 as the value for HD 77361, the normal value of $$\mathrm{He/H}=0.1$$ He / H = 0.1 . Knowing the amount of He-enhancement in the Li-rich giants is a strong clue for understanding the scenarios responsible for the Li and He enrichment. The analysis and results are discussed.

中文翻译：

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超富锂巨型 HD 77361 中氦增强的研究

在这项工作中，利用 MgH 带和 Mg i 线的强度研究了富锂 (Li-rich) K 巨星 HD 77361 中的氦增强 (He-enhancement)。已经对 HD 77361 进行了详细的丰度分析以及 MgH 带和 Mg i 谱线的合成。人们可以预期，在不确定性范围内，MgH 和 Mg i 谱线的镁丰度相同。但是，我们发现来自 MgH 线的 Mg 丰度明显低于来自 Mg i 线的丰度，并且这种差异不能通过在不确定性内改变恒星参数来调和，这意味着恒星光球层中的 He 增强。大气中的 He 增强是通过使用不同 He/H 比率的模型来估计的，因此两条线 MgH 和 Mg i 返回相同的 Mg 丰度，适用于采用的模型的 He/H 比率。我们发现 $$\mathrm{He/H}=0.4\pm 0.1$$ He / H = 0.4 ± 0.1 作为 HD 77361 的值，正常值 $$\mathrm{He/H}=0.1$$ He /H = 0.1。了解富锂巨人中 He 增强的数量是理解导致 Li 和 He 富集的场景的有力线索。讨论了分析和结果。