We use observations from the 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 2018 to identify and characterise stellar multiples with periods below 30 years, corresponding to $\Delta$RV$_{max}\gtrsim$ 3 km s$^{-1}$, where $\Delta$RV$_{max}$ 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 anti-correlation between the close binary fraction and [Fe/H], we find that high abundances of $\alpha$ elements also suppress multiplicity at most values of [Fe/H] sampled by APOGEE. The anti-correlation between $\alpha$ 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 disks and their propensity for fragmentation via gravitational stability. Near [Fe/H] = 0, the bias-corrected close binary fraction ($a<10$ au) decreases from $\approx$ 100\% at [$\alpha$/H] = $-$0.2 to $\approx$ 15\% near [$\alpha$/H] = 0.08, with a suggestive turn-up to $\approx$20\% near [$\alpha$/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.

中文翻译：

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作为 APOGEE 中恒星参数函数的接​​近二元分数：与 α 丰度的强反相关

我们使用 APOGEE 调查的观测结果来探索恒星参数与多样性之间的关系。我们将 41,363 颗矮星和次巨星的高分辨率重复光谱与来自 APOGEE 管道的丰度测量以及使用来自 Sanders & Das 2018 年的 Gaia DR2 视差得出的距离和恒星参数相结合，以识别和表征周期低于 30 年的恒星倍数，对应于 $ \Delta$RV$_{max}\gtrsim$ 3 km s$^{-1}$，其中 $\Delta$RV$_{max}$ 是 APOGEE 检测到的最大径向速度偏移。化学成分是我们样本中近二元分数的大部分变化的原因，质量和年龄等恒星参数起次要作用。除了先前确定的紧密二元分数与 [Fe/H] 之间的强反相关之外，我们发现高丰度的 $\alpha$ 元素也会抑制 APOGEE 采样的大多数 [Fe/H] 值的多样性。$\alpha$ 丰度和多样性之间的反相关性比对 Fe 观察到的更陡峭，这表明尘埃和冰形式的 C、O 和 Si 主导着原始原恒星盘的不透明度及其通过引力稳定性破碎的倾向. 在 [Fe/H] = 0 附近，偏差校正的接近二进制分数 ($a<10$ au) 从 [$\alpha$/H] = $-$0.2 处的 $\approx$ 100\% 减少到 $\approx [$\alpha$/H] = 0.08 附近的 $15\%，[$\alpha$/H] = 0.2 附近的 $\approx$20\% 暗示性上涨。我们得出结论，银河系中类太阳矮星的恒星多样性与化学成分之间的关​​系是复杂的，