Dataset of stellar H-alpha activity index for investigation of stellar chromospheric activity based on the LAMOST Medium-Resolution Spectroscopic Survey

This dataset of stellar H-alpha activity index is for investigation of stellar chromospheric activity based on the LAMOST Medium-Resolution Spectroscopic Survey (MRS). High signal-to-noise ratio coadded MRS spectra of F-, G-, and K-type stars (4000-7000 K) in LAMOST Data Release 8 are utilized in the dataset (329,294 spectra in total). H-alpha activity index is employed to quantitatively describe the stellar chromospheric activity level, which is the ratio of the mean flux of H-alpha center band over the mean flux of two continuum bands on the two sides of H-alpha line. The derived H-alpha activity index values (as well as the H-alpha equivalent width values for comparison) and related parameters from the LAMOST catalogs are stored in a CSV format file (file name: Halpha_activity_index_LAMOST_MRS_DR8.csv). Columns in the dataset: obsid - unique observation identifier of LAMOST MRS fitsname - FITS file name of MRS spectra sn_b - signal-to-noise ratio of the blue-band data of MRS sn_r - signal-to-noise ratio of the red-band data of MRS para_band - indicating which band of MRS is used by the LASP for determining the stellar parameters; ‘B’ representing the blue band and ‘R’ representing the red band teff - effective temperature determined by the LASP (unit: K) teff_err - uncertainty of teff (unit: K) logg - surface gravity determined by the LASP (unit: dex) logg_err - uncertainty of logg (unit: dex) feh - metallicity determined by the LASP (unit: dex) feh_err - uncertainty of feh (unit: dex) rv_r0 - radial velocity determined based on the red-band data of MRS (unit: km/s) rv_r0_err - uncertainty of rv_r0 (unit: km/s) category* - ‘main-sequence’ or ‘giant’ or ‘intermediate-zone’ I_halpha* - H-alpha activity index I_halpha_err* - uncertainty of H-alpha activity index W_halpha* - H-alpha equivalent width (unit: Å) (Note: The columns marked with an asterisk are provided by this dataset. Other columns are from the catalogs of LAMOST DR8 v1.1. LASP is an acronym for LAMOST Stellar Parameter Pipeline. A value of -9999.0 in the dataset means not available.)