Distant Relatives: The Chemical Homogeneity of Comoving Pairs Identified in Gaia
Distant Relatives: The Chemical Homogeneity of Comoving Pairs Identified in Gaia
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DOI：
10.3847/1538-4357/ac14be
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发表时间：
2021-04
期刊：
影响因子：
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通讯作者：
T. Nelson;Y. Ting;K. Hawkins;A. Ji;Harshil Kamdar;K. El-Badry
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作者：
T. Nelson;Y. Ting;K. Hawkins;A. Ji;Harshil Kamdar;K. El-Badry
同向运动对，即使是在距离为106的Au处，也是预测的连续恒星的储存库。我们提供了31个共动对中62颗恒星的详细化学丰度，其间距为102-107 Au，三维速度差<2 km s−1。此示例包括绑定的共移动对/宽二进制文件和未绑定的共移动对。观测是使用麦哲伦/克莱望远镜上的麦哲伦稻盛京瓷Echelle（MIKE）摄谱仪以高分辨率（R 45，000）进行的，典型的信噪比为150像素-1。利用这些光谱，我们测量了24种元素的表面丰度，包括Li、C、Na、Mg、Al、Si、Ca、Sc、Ti、V、Cr、Mn、Fe、Co、Ni、Cu、Zn、Sr、Y、Zr、Ba、La、Nd和Eu。以铁为代表元素，我们的宽双星样品是化学均匀的在0.05 dex的水平，这与以前的宽双星的研究。重要的是，即使是分离度为2 × 105-107 Au的系统也是均匀的，达到0.09 dex，而随机对的分散度为0.23 dex。在宽双星和随机双星的混合模型下，我们发现在间距为2 × 10 ~ 5 - 10 ~ 7 Au的同动双星对中，有73 ± 22%是连续的。我们的研究结果意味着，一个更大的相空间参数空间可以用来寻找连续恒星，研究M-矮星，星星团演化，系外行星，化学标记，等等。
Comoving pairs, even at the separations of (106) au, are a predicted reservoir of conatal stars. We present detailed chemical abundances of 62 stars in 31 comoving pairs with separations of 102–107 au and 3D velocity differences <2 km s−1. This sample includes both bound comoving pairs/wide binaries and unbound comoving pairs. Observations were taken using the Magellan Inamori Kyocera Echelle (MIKE) spectrograph on board the Magellan/Clay Telescope at high resolution (R ∼ 45,000) with a typical signal-to-noise ratio of 150 pixel−1. With these spectra, we measure surface abundances for 24 elements, including Li, C, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Y, Zr, Ba, La, Nd, and Eu. Taking iron as the representative element, our sample of wide binaries is chemically homogeneous at the level of 0.05 dex, which agrees with prior studies on wide binaries. Importantly, even systems at separations 2 × 105–107 au are homogeneous to 0.09 dex, as opposed to the random pairs, which have a dispersion of 0.23 dex. Assuming a mixture model of the wide binaries and random pairs, we find that 73 ± 22% of the comoving pairs at separations 2 × 105–107 au are conatal. Our results imply that a much larger parameter space of phase space may be used to find conatal stars, to study M-dwarfs, star cluster evolution, exoplanets, chemical tagging, and beyond.