LAMOST Time-Domain survey: first results of four K2 plates

• Published in: Research in astronomy and astrophysics Vol. 21; no. 11; pp. 292 - 232
• Main Authors: Wang, Song, Zhang, Hao-Tong, Bai, Zhong-Rui, Yuan, Hai-Long, Xiang, Mao-Sheng, Zhang, Bo, Hou, Wen, Zuo, Fang, Du, Bing, Li, Tan-Da, Yang, Fan, Cui, Kai-Ming, Wang, Yi-Lun, Li, Jiao, Kovalev, Mikhail, Li, Chun-Qian, Tian, Hao, Zong, Wei-Kai, Han, Heng-Geng, Liu, Chao, Luo, A-Li, Shi, Jian-Rong, Fu, Jian-Ning, Bi, Shao-Lan, Han, Zhan-Wen, Liu, Ji-Feng
• Format: Journal Article
• Language: English
• Published: Beijing National Astronomical Observatories, CAS and IOP Publishing Ltd 01.12.2021; IOP Publishing; Key Laboratory of Optical Astronomy,National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China%Max-Planck Institute for Astronomy,K?nigstuhl 17,D-69117 Heidelberg,Germany%Department of Astronomy,Beijing Normal University,Beijing 100875,China%School of Physics and Astronomy,University of Birmingham,Birmingham B15 2TT,UK; College of Astronomy and Space Sciences,University of Chinese Academy of Sciences,Beijing 100049,China%Key Laboratory of Optical Astronomy,National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China; Department of Astronomy,Beijing Normal University,Beijing 100875,China%Department of Astronomy,Beijing Normal University,Beijing 100875,China; College of Astronomy and Space Sciences,University of Chinese Academy of Sciences,Beijing 100049,China%Yunnan Astronomical Observatory,Chinese Academy of Sciences,Kunming 650216,China; Max-Planck Institute for Astronomy,K?nigstuhl 17,D-69117 Heidelberg,Germany%Key Lab of Space Astronomy and Technology,National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China; WHU-NAOC Joint Center for Astronomy,Wuhan University,Wuhan 430072,China; Stellar Astrophysics Centre,Department of Physics and Astronomy,Aarhus University,Ny Munkegade 120,DK-8000 Aarhus C,Denmark; Key Laboratory of Optical Astronomy,National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China; College of Astronomy and Space Sciences,University of Chinese Academy of Sciences,Beijing 100049,China%Yunnan Astronomical Observatory,Chinese Academy of Sciences,Kunming 650216,China%Key Laboratory of Optical Astronomy,National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China; College of Astronomy and Space Sciences,University of Chinese Academy of Sciences,Beijing 100049,China; IOP Science
• Subjects: astronomical database: miscellaneous; Astronomy & Astrophysics; ASTRONOMY AND ASTROPHYSICS; binaries: general; binaries: spectroscopic; Binary stars; Curve fitting; Exposure; Light curve; Mathematical analysis; Parameter estimation; Plates; Polls & surveys; Radial velocity; Signal to noise ratio; Spectra; Spectroscopy; stars: fundamental parameters; Stellar activity; Stellar evolution; Time domain analysis; binaries:general; binaries:spectroscopic; astronomical database:miscellaneous; catalogs; stars:fundamental parameters
• ISSN: 1674-4527; 2397-6209
• DOI: 10.1088/1674-4527/21/11/292

From Oct. 2019 to Apr. 2020, LAMOST performed a time-domain (TD) spectroscopic survey of four K2 plates with both low- and medium-resolution observations. The low-resolution spectroscopic survey acquired 282 exposures ( ≈ 46.6 h) over 25 nights, yielding a total of about 767 000 spectra, and the medium-resolution survey took 177 exposures ( ≈ 49.1 h) over 27 nights, collecting about 478 000 spectra. More than 70%/50% of low-resolution/medium-resolution spectra have signal-to-noise ratio higher than 10. We determine stellar parameters (e.g., T 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 values 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 medium-resolution spectra and cross-matching the spatially resolved binary catalog from Gaia EDR3. The LAMOST TD survey is expected to represent a breakthrough in various scientific topics, such as binary systems, stellar activity, stellar pulsation, etc.