Discovery of 2716 hot emission-line stars from LAMOST DR5

TL;DR

This paper presents a new catalog of 3339 hot emission-line stars from LAMOST DR5, including 2716 newly identified stars, using an automated detection method and infrared photometry to classify star types.

Contribution

The study introduces an automated routine for identifying emission-line stars in large spectra datasets and provides a comprehensive, homogeneous catalog including many new detections.

Findings

Identified 3339 hot emission-line stars from LAMOST DR5.

Discovered 2716 new emission-line stars not in SIMBAD.

Classified stars into Classical Be, Ae, and Herbig types using infrared data.

Abstract

We present a catalog of 3339 hot emission-line stars (ELS) identified from 451,695 O, B, and A type spectra, provided by the LAMOST DR5 release. We developed an automated python routine that identified 5437 spectra having a peak between 6561 and 6568~\AA. False detections and bad spectra were removed, leaving 4138 good emission-line spectra of 3339 unique ELS. We re-estimated the spectral type of 3307 spectra as the LAMOST Stellar Parameter Pipeline (LASP) did not provide accurate spectral types for these emission-line spectra. As Herbig Ae/Be stars show higher excess in near-infrared and mid-infrared wavelengths than Classical Ae/Be stars, we used 2MASS and WISE photometry to distinguish them. Finally, we report 1089 Classical Be, 233 Classical Ae, and 56 Herbig Ae/Be stars identified from the LAMOST DR5. In addition, 928 B[em]/A[em] stars and 240 CAe/CBe potential candidates are identified. From our sample of 3339 hot emission-line stars, 2716 ELS identified in this work do not have any record in the SIMBAD database and they can be considered as new detections. Identification of such a large homogeneous set of emission-line spectra will help the community to study the emission phenomenon in detail without worrying about the inherent biases when compiling from various sources.