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Main Authors: Yu, Lihuan, Li, Jiangdan, Wang, Jinliang, He, Tongyu, aa, Zhanwen Han
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2601.05779
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author Yu, Lihuan
Li, Jiangdan
Wang, Jinliang
He, Tongyu
aa, Zhanwen Han
author_facet Yu, Lihuan
Li, Jiangdan
Wang, Jinliang
He, Tongyu
aa, Zhanwen Han
contents Stars that exhibit prominent emission lines in their spectra are referred to as emission-line stars, encompassing a wide range of stellar types and indicative of intriguing physical properties. The Large Sky Area Multi-Object fiber Spectroscopic Telescope (LAMOST) has released millions of spectra from its Medium-Resolution Survey (MRS). A small fraction of these spectra exhibit emission lines, yet they remain undiscovered and unanalyzed due to being buried in the vast dataset. We have developed a method based on Derivative Spectroscopy (DS), which provides a novel approach for detecting and identifying emission-line stars by extracting signals from complex backgrounds and estimating spectral line profiles. Applying this method to the $\mathrm{Hα}$ spectral line profiles from the LAMOST-MRS Data Release 7 (DR7), we compiled a catalog of emission-line stars using the second- and third-derivative spectra for automated peak detection. This approach also facilitates the classification of $\mathrm{Hα}$ emission-line morphologies through a simplified scheme. The catalog comprises 56\,649 spectra with relatively prominent $\mathrm{Hα}$ emission lines from 45\,206 unique stars, with each emission-line component accompanied by approximate estimates of its wavelength, amplitude, and width. All $\mathrm{Hα}$ spectral lines were classified into three morphological classes under a unified classification scheme: single emission peak (83.0 \%), double emission peaks (5.6 \%), and P Cygni-type profiles (11.5 \%), which encompass both P Cygni and inverse P Cygni features. Through cross-referencing with SIMBAD, 39\,497 stars represent new emission-line sources discovered in our research.
format Preprint
id arxiv_https___arxiv_org_abs_2601_05779
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle A Catalog of 45,206 Hα Emission-line Stars from LAMOST MRS DR7
Yu, Lihuan
Li, Jiangdan
Wang, Jinliang
He, Tongyu
aa, Zhanwen Han
Solar and Stellar Astrophysics
Stars that exhibit prominent emission lines in their spectra are referred to as emission-line stars, encompassing a wide range of stellar types and indicative of intriguing physical properties. The Large Sky Area Multi-Object fiber Spectroscopic Telescope (LAMOST) has released millions of spectra from its Medium-Resolution Survey (MRS). A small fraction of these spectra exhibit emission lines, yet they remain undiscovered and unanalyzed due to being buried in the vast dataset. We have developed a method based on Derivative Spectroscopy (DS), which provides a novel approach for detecting and identifying emission-line stars by extracting signals from complex backgrounds and estimating spectral line profiles. Applying this method to the $\mathrm{Hα}$ spectral line profiles from the LAMOST-MRS Data Release 7 (DR7), we compiled a catalog of emission-line stars using the second- and third-derivative spectra for automated peak detection. This approach also facilitates the classification of $\mathrm{Hα}$ emission-line morphologies through a simplified scheme. The catalog comprises 56\,649 spectra with relatively prominent $\mathrm{Hα}$ emission lines from 45\,206 unique stars, with each emission-line component accompanied by approximate estimates of its wavelength, amplitude, and width. All $\mathrm{Hα}$ spectral lines were classified into three morphological classes under a unified classification scheme: single emission peak (83.0 \%), double emission peaks (5.6 \%), and P Cygni-type profiles (11.5 \%), which encompass both P Cygni and inverse P Cygni features. Through cross-referencing with SIMBAD, 39\,497 stars represent new emission-line sources discovered in our research.
title A Catalog of 45,206 Hα Emission-line Stars from LAMOST MRS DR7
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2601.05779