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arXiv · 2109.03149

LAMOST Time-Domain Survey: First Results of four $K$2 plates

Song Wang·Haotong Zhang·Zhongrui Bai·Hailong Yuan·Maosheng Xiang·Bo Zhang·Wen Hou·Fang Zuo·Bing Du·Tanda Li·Fan Yang·Kaiming Cui·Yilun Wang·Jiao Li·Mikhail Kovalev·Chunqian Li·Hao Tian·Weikai Zong·Henggeng Han·Chao Liu·A-Li Luo·Jianrong Shi·Jian-Ning Fu·Shaolan Bi·Zhanwen Han·Jifeng Liu
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Abstract

From Oct. 2019 to Apr. 2020, LAMOST performs a time-domain spectroscopic survey of four $K$2 plates with both low- and med-resolution observations. The low-resolution spectroscopic survey gains 282 exposures ($\approx$46.6 hours) over 25 nights, yielding a total of about 767,000 spectra, and the med-resolution survey takes 177 exposures ($\approx$49.1 hours) over 27 nights, collecting about 478,000 spectra. More than 70%/50% of low-resolution/med-resolution spectra have signal-to-noise ratio higher than 10. We determine stellar parameters (e.g., $T_{\rm eff}$, log$g$, [Fe/H]) and radial velocity (RV) with different methods, including LASP, DD-Payne, and SLAM. In general, these parameter estimations from different methods show good agreement, and the stellar parameter values are consistent with those of APOGEE. We use the $Gaia$ DR2 RV data to calculate a median RV zero point (RVZP) for each spectrograph exposure by exposure, and the RVZP-corrected RVs agree well with the APOGEE data. The stellar evolutionary and spectroscopic masses are estimated based on the stellar parameters, multi-band magnitudes, distances and extinction values. Finally, we construct a binary catalog including about 2700 candidates by analyzing their light curves, fitting the RV data, calculating the binarity parameters from med-resolution spectra, and cross-matching the spatially resolved binary catalog from $Gaia$ EDR3. The LAMOST TD survey is expected to get breakthrough in various scientific topics, such as binary system, stellar activity, and stellar pulsation, etc.

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Song Wang, Haotong Zhang, Zhongrui Bai, Hailong Yuan, Maosheng Xiang, Bo Zhang, Wen Hou, Fang Zuo, Bing Du, Tanda Li, Fan Yang, Kaiming Cui, Yilun Wang, Jiao Li, Mikhail Kovalev, Chunqian Li, Hao Tian, Weikai Zong, Henggeng Han, Chao Liu, A-Li Luo, Jianrong Shi, Jian-Ning Fu, Shaolan Bi, Zhanwen Han, Jifeng Liu. 2021-09-07. LAMOST Time-Domain Survey: First Results of four $K$2 plates. https://doi.org/10.1088/1674-4527/21/11/292

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