Identification Of A-type Supergiants From LAMOST Data Release

We have established a method for selecting A-type supergiants from the LAMOST data by using the spectral index,and we have successfully identified 121 A-type supergiants(includes 54 star spectra of luminosity type I,33 star spectra of luminosity type I-II,and 34 star spectra of luminosity type II).First,we select a larger A-type star candidate from the spatial distribution of the line index as a research sample,and then further select a A-type supergiant candidate sample from the A-type star candidate sample through the line index condition.This candidate sample has 45357 spectras.Then we further screened these stars by the spectral characteristics of A-type supergiants and human eyes,and finally obtained 121 A-type supergiants spectra(111 stars).A multi-faceted analysis of the A-type supergiant samples revealed that the number of stars of the A4-A7 in the A-type supergiant samples was relatively small.In order to check the reliability of the samples,we used the software package MKCLASS to perform template matching on the A-type supergiant samples,and found that the MKCLASS template matching can give more reliable classification results in general,but some star spectra were severely misclassified,and some did not give the results of the classification.In addition,by studying the spatial distribution of the samples,we also found that most of the A-type supergiants are distributed on the galactic disk,but 10 of them are distributed in the high galactic latitude area(glat>20° or glat<-20°).We will perform further high-resolution spectroscopy observations and analysis on them.