Phase II of the LAMOST-Kepler/K2 survey. I. Time series of medium-resolution spectroscopic observations

• Published in: arXiv.org 2020-09
• Main Authors: Zong, Weikai, Jian-Ning Fu, De Cat, Peter, Wang, Jiaxin, Shi, Jianrong, Luo, Ali, Zhang, Haotong, Frasca, A, J Molenda- Żakowicz, Gray, R O, Corbally, C J, Catanzaro, G, Cang, Tianqi, Wang, Jiangtao, Chen, Jianjun, Hou, Yonghui, Liu, Jiaming, Niu, Hubiao, Pan, Yang, Tian, Hao, Yan, Hongliang, Zhang, Yong, Zuo, Heng
• Format: Article
• Language: English
• Subjects: Gaussian distribution; Gravitation; Metallicity; Normal distribution; Parameters; Radial velocity; Spectra; Stars
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2009.06843

Phase \RNum{2} of the LAMOST-{\sl Kepler/K}2 survey (LK-MRS), initiated in 2018, aims at collecting medium-resolution spectra (\(R\sim7,500\); hereafter MRS) for more than \(50,000\) stars with multiple visits (\(\sim60\) epochs) over a period of 5 years (2018 September to 2023 June). We selected 20 footprints distributed across the {\sl Kepler} field and six {\sl K}2 campaigns, with each plate containing a number of stars ranging from \(\sim2,000\) to \(\sim 3,000\). During the first year of observations, the LK-MRS has already collected \(\sim280,000\) and \(\sim369,000\) high-quality spectra in the blue and red wavelength range, respectively. The atmospheric parameters and radial velocities for \(\sim259,000\) spectra of \(21,053\) targets were successfully calculated by the LASP pipeline. The internal uncertainties for the effective temperature, surface gravity, metallicity, and radial velocity are found to be \(100\)\,K, \(0.15\)\,dex, \(0.09\)\,dex, and \(1.00\)\,km\,s\(^{-1}\), respectively. We found \(14,997\), \(20,091\), and \(1,514\) stars in common with the targets from the LAMOST low-resolution survey (LRS), GAIA and APOGEE, respectively, corresponding to a fraction of \(\sim70\%\), \(\sim95\%\) and \(\sim7.2\%\). In general, the parameters derived from LK-MRS spectra are consistent with those obtained from the LRS and APOGEE spectra, but the scatter increases as the surface gravity decreases when comparing with the measurements from APOGEE. A large discrepancy is found with the GAIA values of the effective temperature. The comparisons of radial velocities of LK-MRS to GAIA and LK-MRS to APOGEE nearly follow an Gaussian distribution with a mean \(\mu\sim1.10\) and \(0.73\)\,km\,s\(^{-1}\), respectively.