Metallic-line Stars Identified from Low-resolution Spectra of LAMOST DR5

doi:10.3847/1538-4365/ab17d8

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	Metallic-line Stars Identified from Low-resolution Spectra of LAMOST DR5
	Qin,Li 1,2,3; Luo,A-Li 1,2,3,4; Hou,Wen 1; Li,Yin-Bi 1; Zhang,Shuo 1,3; Wang,Rui 1,3; Wang,Li-Li 1,2,3; Kong,Xiao 1,3; Han,Jin-Shu 2
刊名	The Astrophysical Journal Supplement Series
	2019-05-29
卷号	242 期号:2
关键词	catalogs infrared: stars methods: data analysis methods: statistical stars: chemically peculiar surveys
ISSN号	0067-0049
DOI	10.3847/1538-4365/ab17d8
英文摘要	Abstract The Large Sky Area Multi-Object Fibre Spectroscopic Telescope data release 5 (DR5) released more than 200,000 low-resolution spectra of early-type stars with a signal-to-noise ratio ?>?50. The search for metallic-line (Am) stars in such a large database and a study of their statistical properties are presented in this paper. Six machine-learning algorithms were experimented with using known Am spectra, and both the empirical criteria method and the MKCLASS package were also investigated. Comparing their performance, the random forest (RF) algorithm won, not only because the RF has high successful rate, but because it can also derive rank features. Then the RF was applied to the early-type stars of DR5, and 15,269 Am candidates were picked out. Manual identification was conducted based on the spectral features derived from the RF algorithm; 9372 Am stars and 1131 Ap candidates were compiled into a catalog. Statistical studies were conducted including temperature distribution, space distribution, and infrared photometry. The spectral types of Am stars are mainly between F0 and A4 with a peak around A7, which is similar to previous works. With the Gaia distances, we calculated the vertical height Z from the Galactic plane for each Am star. The distribution of Z suggests that the incidence rate of Am stars shows a descending gradient with an increasing . On the other hand, Am stars do not show a noteworthy pattern in the infrared band. As the wavelength gets longer, the infrared excess of Am stars decreases, until there is little or no excess in W1 and W2 bands.
语种	英语
出版者	The American Astronomical Society
WOS记录号	IOP:0067-0049-242-2-AB17D8
内容类型	期刊论文
源URL	[http://ir.bao.ac.cn/handle/114a11/26415]
专题	中国科学院国家天文台
作者单位	1.Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, People’s Republic of China lal@nao.cas.cn 2.School of Information Management & Institute for Astronomical Science, Dezhou University, Dezhou 253023, People’s Republic of China 3.University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China 4.Department of Physics and Astronomy, University of Delaware, Newark, DE 19716, USA
推荐引用方式 GB/T 7714	Qin,Li,Luo,A-Li,Hou,Wen,et al. Metallic-line Stars Identified from Low-resolution Spectra of LAMOST DR5[J]. The Astrophysical Journal Supplement Series,2019,242(2).
APA	Qin,Li.,Luo,A-Li.,Hou,Wen.,Li,Yin-Bi.,Zhang,Shuo.,...&Han,Jin-Shu.(2019).Metallic-line Stars Identified from Low-resolution Spectra of LAMOST DR5.The Astrophysical Journal Supplement Series,242(2).
MLA	Qin,Li,et al."Metallic-line Stars Identified from Low-resolution Spectra of LAMOST DR5".The Astrophysical Journal Supplement Series 242.2(2019).