LAMOST Medium-Resolution Spectroscopic Survey (LAMOST-MRS): Binarity and Exotic Star

LAMOST-MRS-B is one of the sub-surveys of LAMOST medium-resolution ($R\sim7500$) spectral survey and aims at studying the statistical properties of binary stars and exotic stars. We intend to observe about 30,000 stars ($10\leq G < 14.5$ mag) with at least 10 visits in five years. We first planned to observe 25 plates around the Galactic plane in 2018. Then the plates were reduced to 12 in 2019 because of the limitation of observation. At the same time, two new plates located at the high Galactic Latitude were added to explore binary properties influenced by the different environments. In this survey project, we set the identified exotic and low-metallicity stars with the highest observation priorities. For the rest of the selected sources, we gave the higher priority to the relatively brighter stars in order to obtain good quality spectra as many as possible. There are 49,129 sources observed in LAMOST-MRS-B field of DR8, of which 28,828 and 3,375 sources are visited more than twice and ten times with $\rm SNR \geq 10$, respectively. Most of the sources are B-, A-, and F-type stars with $\rm -0.6< [Fe/H] < 0.4 $ dex. We also obtain 347 identified variable and exotic stars and about 250 stars with $\rm [Fe/H] <-1$ dex. We measure radial velocities (RVs) by using 892,233 spectra of the sources. The uncertainties of RV achieve about $1$ and $10$ km/s for 95\% of late- and early-type stars, respectively.There are two catalogs, which are fits (Flexible Image Transport System) files. They can be read by TOPCAT or other packages (such as astropy of python, we provide an example named read_catalog.ipynb in the Supplementary Materials).Catalog1 is a table that contains the epoch radial velocity data points and median values of the stellar atmospheric parameters for 49,129 stars observed in the LAMOST-MRS-B field. Each entry is a radial velocity in the solar barycentric reference frame for a given object and observation time.Catalog2 is a table that contains the type of exotic stars and their celestial coordinates, which compiled exotic (or variable) stars discoveries in the literature.The description of each column can be found in the file catalog_description.pdf