MINING THE SLOAN DIGITAL SKY SURVEY IN SEARCH OF EXTREMELY alpha-POOR STARS IN THE GALAXY

	MINING THE SLOAN DIGITAL SKY SURVEY IN SEARCH OF EXTREMELY alpha-POOR STARS IN THE GALAXY
	Xing, Q. F.1,2; Zhao, G.1
刊名	ASTROPHYSICAL JOURNAL
	2014-07-20
卷号	790 期号:1
关键词	methods: data analysis stars: abundances stars: atmospheres
英文摘要	As we know, the majority of metal-poor Galactic halo stars appear to have chemical abundances that were enhanced by alpha-elements (e.g., O, Mg, Si, Ca, and Ti) during the early stage of the Galaxy. Observed metal-poor halo stars preserved this pattern by exhibiting abundance ratios [alpha/Fe] similar to +0.4. A few striking exceptions that show severe departures from the general enhanced alpha-element chemical abundance trends of the halo have been discovered in recent years. They possess relatively low [alpha/Fe] compared to other comparable-metallicity stars, with abundance ratios over 0.5 dex lower. These stars may have a different chemical enrichment history from the majority of the halo. Similarly, low-alpha abundances are also displayed by satellite dwarf spheroidal (dSph) galaxies. We present a method to select extremely alpha-poor (EAP) stars from the SDSS/SEGUE survey. The method consists of a two-step approach. In the first step, we select suspected metal-poor ([Fe/H] < -0.5) and alpha-poor ([Mg/Fe] < 0) stars as our targets. In the second step, we determine [Mg/Fe] from low-resolution (R = 2000) stellar spectra for our targets and select stars with [Mg/Fe] < -0.1 as candidate EAP stars. In a sample of 40,000 stars with atmospheric parameters in the range of T-eff = [4500, 7000] K, log g = [1.0, 5.0], and [Fe/H] = [-4.0, +0.5], 14 candidate stars were identified. Three of these stars are found to have already been confirmed by other research.
收录类别	SCI
语种	英语
WOS记录号	WOS:000338836800033
内容类型	期刊论文
源URL	[http://ir.bao.ac.cn/handle/114a11/6399]
专题	国家天文台_光学天文研究部
作者单位	1.Chinese Acad Sci, Natl Astron Observ, Key Lab Opt Astron, Beijing 100012, Peoples R China 2.Univ Chinese Acad Sci, Beijing 100049, Peoples R China
推荐引用方式 GB/T 7714	Xing, Q. F.,Zhao, G.. MINING THE SLOAN DIGITAL SKY SURVEY IN SEARCH OF EXTREMELY alpha-POOR STARS IN THE GALAXY[J]. ASTROPHYSICAL JOURNAL,2014,790(1).
APA	Xing, Q. F.,&Zhao, G..(2014).MINING THE SLOAN DIGITAL SKY SURVEY IN SEARCH OF EXTREMELY alpha-POOR STARS IN THE GALAXY.ASTROPHYSICAL JOURNAL,790(1).
MLA	Xing, Q. F.,et al."MINING THE SLOAN DIGITAL SKY SURVEY IN SEARCH OF EXTREMELY alpha-POOR STARS IN THE GALAXY".ASTROPHYSICAL JOURNAL 790.1(2014).