The close binary fraction as a function of stellar parameters in APOGEE: a strong anticorrelation with α abundances
The close binary fraction as a function of stellar parameters in APOGEE: a strong anticorrelation with α abundances
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DOI：
10.1093/mnras/staa2859
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发表时间：
2020-07
影响因子：
4.8
通讯作者：
C. Mazzola;C. Badenes;M. Moe;Sergey E. Koposov;M. Kounkel;K. Kratter;K. Covey;M. Walker;T. Thompson;B. Andrews;P. Freeman;B. Anguiano;J. Carlberg;Nathan M De Lee-Nathan-M-De Lee-2126330873;P. Frinchaboy;H. Lewis;S. Majewski;D. Nidever;C. Nitschelm;A. Price-Whelan;A. Roman-Lopes;K. Stassun;N. Troup
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作者：
C. Mazzola;C. Badenes;M. Moe;Sergey E. Koposov;M. Kounkel;K. Kratter;K. Covey;M. Walker;T. Thompson;B. Andrews;P. Freeman;B. Anguiano;J. Carlberg;Nathan M De Lee-Nathan-M-De Lee-2126330873;P. Frinchaboy;H. Lewis;S. Majewski;D. Nidever;C. Nitschelm;A. Price-Whelan;A. Roman-Lopes;K. Stassun;N. Troup
我们使用从阿帕奇点天文台银河演化实验（APOGEE）调查的观测，探讨恒星参数和多重性之间的关系。我们联合收割机了41363颗矮星和亚巨星的高分辨率重复光谱，以及来自APOGEE管道的丰度测量和使用Sanders & Das的Gaia DR 2视差导出的距离和恒星参数，以识别和表征周期小于30年的恒星多次波，对应于ΔRVmax <$3 km s−1，其中ΔRVmax是APOGEE检测到的径向速度的最大偏移。化学成分是我们样本中近距离双星分数变化的主要原因，恒星参数如质量和年龄起着次要作用。除了先前确定的紧密二元分数和[Fe/H]之间的强相互关系外，我们发现α元素的高丰度也抑制了APOGEE采样的[Fe/H]的大多数值的多重性。α丰度和多重性之间的关系比Fe的关系要陡峭得多，这表明以尘埃和冰的形式存在的C、O和Si主导了原始原恒星盘的不透明度及其通过引力稳定性进行碎裂的倾向。在[Fe/H] = 0 dex附近，偏置校正后的密近双星分数（a < 10 Au）从[α/H] = −0.2 dex时的100%下降到[α/H] = 0.08 dex附近的15%，在[α/H] = 0.2附近可能上升到20%。我们的结论是恒星的多样性和化学成分之间的关系，在银河系领域的类太阳矮星是复杂的，这种复杂性应占在未来的研究相互作用的双星。
We use observations from the Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey to explore the relationship between stellar parameters and multiplicity. We combine high-resolution repeat spectroscopy for 41 363 dwarf and subgiant stars with abundance measurements from the APOGEE pipeline and distances and stellar parameters derived using Gaia DR2 parallaxes from Sanders & Das to identify and characterize stellar multiples with periods below 30 yr, corresponding to ΔRVmax ≳ 3 km s−1, where ΔRVmax is the maximum APOGEE-detected shift in the radial velocities. Chemical composition is responsible for most of the variation in the close binary fraction in our sample, with stellar parameters like mass and age playing a secondary role. In addition to the previously identified strong anticorrelation between the close binary fraction and [Fe/H], we find that high abundances of α elements also suppress multiplicity at most values of [Fe/H] sampled by APOGEE. The anticorrelation between α abundances and multiplicity is substantially steeper than that observed for Fe, suggesting C, O, and Si in the form of dust and ices dominate the opacity of primordial protostellar discs and their propensity for fragmentation via gravitational stability. Near [Fe/H] = 0 dex, the bias-corrected close binary fraction (a < 10 au) decreases from ≈100 per cent at [α/H] = −0.2 dex to ≈15 per cent near [α/H] = 0.08 dex, with a suggestive turn-up to ≈20 per cent near [α/H] = 0.2. We conclude that the relationship between stellar multiplicity and chemical composition for sun-like dwarf stars in the field of the Milky Way is complex, and that this complexity should be accounted for in future studies of interacting binaries.