Double-lined Spectroscopic Binaries in the APOGEE DR16 and DR17 Data
Double-lined Spectroscopic Binaries in the APOGEE DR16 and DR17 Data
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DOI：
10.3847/1538-3881/ac1798
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发表时间：
2021-07
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通讯作者：
M. Kounkel;K. Covey;K. Stassun;A. Price-Whelan;J. Holtzman;D. Chojnowski;P. Longa-Peña;C. Román-Zú
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作者：
M. Kounkel;K. Covey;K. Stassun;A. Price-Whelan;J. Holtzman;D. Chojnowski;P. Longa-Peña;C. Román-Zú
APOGEE光谱在测量恒星径向速度时提供了1.01 km s-1的精度。即使当多颗恒星被捕获在同一光谱中时，这也是成立的，就像双线光谱联星（SB 2）最常见的情况一样，尽管也可能发生不相关恒星的随机视线对准。我们开发了一个代码，自主识别SB 2和高阶多次波的APOGEE光谱，导致7273候选SB 2，813 SB 3和19 SB 4。我们估计了双星的质量比，并对这些系统的一个子集进行了足够数量的测量，我们进行了完整的轨道拟合，证实了大多数周期<10天的系统已经圆化。总的来说，我们发现在主序星矮星中，SB 2分数（F SB 2）为1.3%，并且F SB 2随星星温度的变化没有明显的趋势。我们也能够在金属丰度较低的来源中恢复较高的F SB 2，但存在一些观测偏差。我们还检查了TESS的光变曲线，以确定这些光谱双星中哪些也是日食。这样的系统，特别是那些也是主序前后的系统，是进行后续分析以确定其质量和温度的良好候选者。
APOGEE spectra offer ≲1 km s−1 precision in the measurement of stellar radial velocities. This holds even when multiple stars are captured in the same spectrum, as happens most commonly with double-lined spectroscopic binaries (SB2s), although random line-of-sight alignments of unrelated stars can also occur. We develop a code that autonomously identifies SB2s and higher order multiples in the APOGEE spectra, resulting in 7273 candidate SB2s, 813 SB3s, and 19 SB4s. We estimate the mass ratios of binaries, and for a subset of these systems with a sufficient number of measurements we perform a complete orbital fit, confirming that most systems with periods of <10 days have circularized. Overall, we find an SB2 fraction (F SB2) ∼ 3% among main-sequence dwarfs, and that there is not a significant trend in F SB2 with temperature of a star. We are also able to recover a higher F SB2 in sources with lower metallicity, however there are some observational biases. We also examine light curves from TESS to determine which of these spectroscopic binaries are also eclipsing. Such systems, particularly those that are also pre- and post-main sequence, are good candidates for a follow-up analysis to determine their masses and temperatures.