Determination of Distance, extinction, Mass, and Age for Stars in LAMOST DR7


 Large scale spectroscopic surveys such as LAMOST have collected spectra of millions stars in the Milky Way. Using this huge sample of stars to study the assembling history and structure of our Galaxy requires accurate estimates of distance, extinction, age, and mass for individual stars. Combining the parallax constraint from Gaia EDR3, with Bayesian inference we have estimated the distance and extinction for stars observed in LAMOST DR7, as well as the stellar mass and age for evolved stars in this data release. We validated the accuracies of the stellar parameters by comparing our results against various measurements, including star-pair techenique, asteroseismology, globular clus- ters, and isochrone fits to main-sequence stars and subgiants. This is a valuable catalog of stellar parameters under a Bayesian framework estimated using the data from Gaia EDR3 and LAMOST spectroscopic data. With this data set we explored the stellar popu- lation of Galactic massive substructure, Gaia-Sausage-Enceladus (GSE). The kinematically selected members of GSE have a median metallicity of [Fe/H]= −1.29 and a median age of 11.6 Gyr.