학술논문
LAMOST Time-Domain Survey: First Results of four $K$2 plates
Document Type
Working Paper
Author
Wang, Song; Zhang, Haotong; Bai, Zhongrui; Yuan, Hailong; Xiang, Maosheng; Zhang, Bo; Hou, Wen; Zuo, Fang; Du, Bing; Li, Tanda; Yang, Fan; Cui, Kaiming; Wang, Yilun; Li, Jiao; Kovalev, Mikhail; Li, Chunqian; Tian, Hao; Zong, Weikai; Han, Henggeng; Liu, Chao; Luo, A-Li; Shi, Jianrong; Fu, Jian-Ning; Bi, Shaolan; Han, Zhanwen; Liu, Jifeng
Source
Subject
Language
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.
Comment: 22 pages, 19 figures, 7 tables. Accepted for publication in RAA
Comment: 22 pages, 19 figures, 7 tables. Accepted for publication in RAA