The Relative Calibration of Radial Velocity for LAMOST Medium Resolution Stellar Spectra

Xiong, Jianping; Zhang, Bo; Liu, Chao; Li, Jiao; Zhao, Yongheng; Hou, Yonghui

doi:10.48550/arxiv.2108.07483

Cited by 1 publication

(3 citation statements)

References 15 publications

(17 reference statements)

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“…The RV measurement is a vital ingredient of this study since detecting significant RV variations relies on RV differences. We adopted the maximum likelihood method described in Xiong et al (2021) to measure the relative RVs. We briefly describe the procedures as follows.…”

Section: Rv Measurementsmentioning

confidence: 99%

“…This means that the influence of uncorrected RV on the derived binary fraction is little and can be ignored. We also compared the observed binary fraction based on the RVs from Zhang et al (2021) and Xiong et al (2021) and found that the difference between the observed binary fractions derived in the two ways is less than 1.5%. Therefore, we kept using the RV rel from Xiong et al (2021) in the following analysis.…”

Section: Rv Measurementsmentioning

confidence: 99%

“…We also compared the observed binary fraction based on the RVs from Zhang et al (2021) and Xiong et al (2021) and found that the difference between the observed binary fractions derived in the two ways is less than 1.5%. Therefore, we kept using the RV rel from Xiong et al (2021) in the following analysis. In our final sample of 9382 candidates, only 2911 stars were observed more than twice (see column 3 in Table 3).…”

Section: Rv Measurementsmentioning

confidence: 99%

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The Binarity of Early-type Stars from LAMOST medium-resolution Spectroscopic Survey

Guo

Xiong

et al. 2022

Res. Astron. Astrophys.

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Massive binaries play significant roles in many fields. Identification of massive stars, particularly massive binaries, is of great importance. In this paper, by adopting the technique of measuring the equivalent widths of several spectral lines, we identified 9,382 early-type stars from LAMOST medium-resolution survey and divided the sample into four groups, T1 ($\sim$O-B4), T2 ($\sim$B5), T3 ($\sim$B7), and T4 ($\sim$B8-A). The relative radial velocities $RV_{\rm rel}$ were calculated using the Maximum Likelihood Estimation. The stars with significant changes of $RV_{\rm rel}$ and at least larger than 15.57km s$^{-1}$ were identified as spectroscopic binaries. We found that the observed spectroscopic binary fractions for the four groups are $24.6\%\pm0.5\%$, $20.8\%\pm0.6\%$, $13.7\%\pm0.3\%$, and $7.4\%\pm0.3\%$, respectively. Assuming that orbital period ($P$) and mass ratio ($q$) have intrinsic distributions as $f(P) \propto P^\pi$ (1\textless$P$\textless1000 days) and $f(q) \propto q^\kappa$ (0.1\textless$q$\textless1), respectively, we conducted a series of Monte-Carlo simulations to correct observational biases for estimating the intrinsic multiplicity properties. The results show that the intrinsic binary fractions for the four groups are 68$\%\pm8\%$, 52$\%\pm3\%$, 44$\%\pm6\%$, and 44$\%\pm6\%$, respectively. The best estimated values for $\pi$ are -1$\pm0.1$, -1.1$\pm0.05$, -1.1$\pm0.1$, and -0.6$\pm0.05$, respectively. The $\kappa$ cannot be constrained for groups T1 and T2 and is -2.4$\pm0.3$ for group T3 and -1.6$\pm0.3$ for group T4. We confirmed the relationship of a decreasing trend in binary fractions towards late-type stars. No correlation between the spectral type and the orbital period distribution has been found yet, possibly due to the limitation of observational cadence.

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Section: Rv Measurementsmentioning

confidence: 99%