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arXiv · 2507.19751

Phase II of the LAMOST-Kepler/K2 Survey. II. Time Domain of Medium-resolution Spectroscopic Observations from 2018 to 2023

Mingfeng Qin·Jian-Ning Fu·Weikai Zong·Peter De Cat·Antonio Frasca·Tianqi Cang·Jiangtao Wang·Jianrong Shi·Ali Luo·Haotong Zhang·Hongliang Yan·J. Molenda- Żakowicz·R. O. Gray·Jiaxin Wang
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Abstract

The LAMOST-Kepler/K2 Medium-Resolution Spectroscopic Survey (LK-MRS) conducted time-domain medium-resolution spectroscopic observations of 20 LAMOST plates in the Kepler and K2 fields from 2018 to 2023, a phase designated as LK-MRS-I. A catalog of stellar parameters for a total of 36,588 stars, derived from the spectra collected during these five years, including the effective temperature, the surface gravity, the metallicity, the {\alpha}-element abundance, the radial velocity, and v sin i of the target stars, is released, together with the weighted averages and uncertainties. At S/N = 10, the measurement uncertainties are 120 K, 0.18 dex, 0.13 dex, 0.08 dex, 1.9 km/s, and 4.0 km/s for the above parameters, respectively. Comparisons with the parameters provided by the APOGEE and GALAH surveys validate the effective temperature and surface gravity measurements, showing minor discrepancies in metallicity and {\alpha}-element abundance values. We identified some peculiar star candidates, including 764 metal-poor stars, 174 very metal-poor stars, and 30 high-velocity stars. Moreover, we found 2,333 stars whose radial velocity seems to be variable. Using Kepler/K2 or TESS photometric data, we confirmed 371 periodic variable stars among the radial velocity variable candidates and classified their variability types. LK-MRS-I provides spectroscopic data being useful for studies of the Kepler and K2 fields. The LK-MRS project will continue collecting time-domain medium-resolution spectra for target stars during the third phase of LAMOST surveys, providing data to support further scientific research.

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Mingfeng Qin, Jian-Ning Fu, Weikai Zong, Peter De Cat, Antonio Frasca, Tianqi Cang, Jiangtao Wang, Jianrong Shi, Ali Luo, Haotong Zhang, Hongliang Yan, J. Molenda- Żakowicz, R. O. Gray, Jiaxin Wang. 2025-07-26. Phase II of the LAMOST-Kepler/K2 Survey. II. Time Domain of Medium-resolution Spectroscopic Observations from 2018 to 2023. https://arxiv.org/abs/2507.19751

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