Qin, Mingfeng ; Fu, Jian-Ning ; Zong, Weikai ; De Cat, Peter ; Frasca, Antonio ; Cang, Tianqi ; Wang, Jiangtao ; Shi, Jianrong ; Luo, Ali ; Zhang, Haotong ; Yan, Hongliang ; Molenda-Żakowicz, Joanna ; Gray, Richard O. ; Wang, Jiaxin

published in The Astrophysical Journal Supplement Series, 280 issue 1, pp. id.19 (1--14) (2025)

Abstract: The LAMOST-Kepler/K2 Medium-Resolution Spectroscopic Survey (LK-MRS) conducted time-domain (TD) 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 5 yr, including the effective temperature, the surface gravity, the metallicity, the α-element abundance, the radial velocity (RV), and vsini of the target stars, is released, together with the weighted averages and uncertainties. At a signal-to-noise ratio = 10, the measurement uncertainties are 120 K, 0.18 dex, 0.13 dex, 0.08 dex, 1.9 km s‑1, and 4.0 km s‑1 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 α-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 2333 stars whose RV seems to be variable. Using Kepler/K2 or TESS photometric data, we confirmed 371 periodic variable stars among the RV variable candidates and classified their variability types. LK-MRS-I provides spectroscopic data that is useful for studies of the Kepler and K2 fields. The LK-MRS project will continue collecting TD medium-resolution spectra for target stars during the third phase of LAMOST surveys, providing data to support further scientific research.

Keyword(s): Spectroscopy ; Catalogs ; Surveys ; Astronomy databases ; Fundamental parameters of stars ; Solar and Stellar Astrophysics
DOI: 10.3847/1538-4365/adf1a9