arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新，休息一下吧，周末愉快~~
arXiv 1409.3543astro-ph.SR
收藏

古老的富金属恒星中的重元素

Heavy elements in old very metal-rich stars

M. Trevisan, B. Barbuy

备注：
16 pages, to appear in A&A
发表信息：
A&A 570, A22 (2014)
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

我们研究了从NLTT目录中选出的一个高自行、古老和富含金属的矮星样本。这些太阳邻居星的低近心距离和偏心轨道表明它们可能起源于银河系内部。化学标记可以探测恒星星族的形成历史。为了确定71个富含金属的矮星样本的起源，我们导出了中子捕获元素Y，Ba，La和Eu的丰度。光谱分析的基础上获得的光学高分辨率阶梯光谱与FEROS摄谱仪在ESO 1.52米望远镜在拉西拉，智利。Y，Ba，La和Eu的丰度通过LTE分析得出，采用MARCS模型大气。Y，Ba，La和Eu的丰度与Fe和Mg作为参考元素的丰度表明我们的富含金属的古老矮星样本和薄盘之间的相似性。另一方面，使用O作为参考元素的丰度比，以及它们的运动学，表明我们的样品明显不同于薄盘星。它们可能是旧的内部薄盘恒星，如前所述，或隆起恒星。在这两种情况下，它们都是从银河系内部迁移到太阳附近的。

英文摘要：

We studied a sample of high proper motion, old and metal-rich dwarf stars, selected from the NLTT catalogue. The low pericentric distances and eccentric orbits of these solar neighbourhood stars indicate that they might have originated in the inner parts of the Galaxy. Chemical tagging can probe the formation history of stellar populations. To identify the origin of a sample of 71 very metal-rich dwarf stars, we derive the abundances of the neutron-capture elements Y, Ba, La, and Eu. The spectroscopic analysis is based on optical high-resolution echelle spectra obtained with the FEROS spectrograph at the ESO 1.52-m Telescope at La Silla, Chile. The abundances of Y, Ba, La, and Eu were derived through LTE analysis, employing the MARCS model atmospheres. The abundances of Y, Ba, La, and Eu vs. Fe and Mg as the reference elements indicate similarities between our sample of old metal-rich dwarf stars and the thin disk. On the other hand, the abundance ratios using O as the reference element, as well as their kinematics, suggest that our sample is clearly distinct from the thin-disk stars. They could be old inner thin-disk stars, as suggested previously, or bulge stars. In either cases they would have migrated from the inner parts of the Galaxy to the solar neighbourhood.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

↑