Abundances and search for vertical stratification in the atmospheres of four HgMn stars
Abundances and search for vertical stratification in the atmospheres of four HgMn stars
复制标题
四颗 HgMn 星大气中的丰度和垂直分层的搜索
DOI：
--
复制
发表时间：
2010
期刊：
影响因子：
--
通讯作者：
G. Wade
中科院分区：
文献类型：
--
作者：
M. Thiam;F. Leblanc;V. Khalack;G. Wade
利用高分辨率、高信噪比的紫外可见光谱资料，我们对4颗HgMn星（HD 71066、HD 175640、HD 178065和HD 221507）进行了详细的光谱分析。利用光谱合成方法，得到了16种元素的22种离子的平均光球化学丰度。我们发现我们的衍生丰度和以前发表的其他作者之间的协议。对于5个元素，目前有足够数量的合适的线，我们试图通过分析导出的丰度作为光学深度的函数的依赖性来检测垂直化学分层。对于大多数元素和大多数恒星，我们没有发现化学分层的证据，其典型的3σ上限为Δ log Nelem/Ntot 0.1 - 0.2 dex每单位光学深度。然而，对于锰在大气中的HD 178065，我们发现令人信服的证据分层。使用Mn丰度的两步模型对谱线轮廓进行建模，得到局部丰度在光学深度范围log τ5000 = −3.6至− 2.8内近似线性变化Δ x0.7 dex。
Using high resolution, high-S/N archival UVES spectra, we have performed a detailed spectroscopic analysis of 4 chemically peculiar HgMn stars (HD 71066, HD 175640, HD 178065 and HD 221507). Using spectrum synthesis, mean photospheric chemical abundances are derived for 22 ions of 16 elements. We find good agreement betwee n our derived abundances and those published previously by other authors. For the 5 el ements that present a sufficient number of suitable lines, we have attempted to detect vertical chemical stratification by analyzing the dependence of derived abundance as a function of optical depth. For most elements and most stars we find no evidence of chemical stratification w ith typical 3σ upper limits of Δ log Nelem/Ntot ∼ 0.1− 0.2 dex per unit optical depth. However, for Mn in the atmosphere of HD 178065 we find convincing evidence of stratification. Mode ling of the line profiles using a two-step model for the abundance of Mn yields a local abundance varying approximately linearly by ∼ 0.7 dex through the optical depth range log τ5000 = −3.6 to ‐2.8.