Exploring the Stellar Rotation of Early-type Stars in the LAMOST Medium-resolution Survey. I. Catalog

Abstract

We derive stellar parameters and abundances ("stellar labels") of 40,034 late-B and A-type main-sequence stars extracted from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope Medium Resolution Survey (LAMOST-MRS). The primary selection of our early-type sample was obtained from LAMOST Data Release 7 based on spectral-line indices. We employed the Stellar Label Machine to derive their spectroscopic stellar parameters, drawing on Kurucz spectral synthesis models with 6000 < T_eff < 15,000 K and -1 < [M/H] < 1 dex. For a signal-to-noise ratio of ~60, the cross validated scatter is ~75 K, 0.06 dex, 0.05 dex, and ~3.5 km s^-1 for T_eff, $\mathrm{log}g$ , [M/H], and $v\sin i$ , respectively. A comparison with objects with prior known stellar labels shows great consistency for all stellar parameters, except for $\mathrm{log}g$ . Although this is an intrinsic caveat that comes from the MRS's narrow wavelength coverage, it only has a minor effect on estimates of the stellar rotation rates because of the decent spectral resolution and the profile-fitting method employed. The masses and ages of our early-type sample stars were inferred from nonrotating stellar evolution models. This paves the way for reviewing the properties of stellar rotation distributions as a function of stellar mass and age.