The Ages and Masses of a Million Galactic-disk Main-sequence Turnoff and Subgiant Stars from the LAMOST Galactic Spectroscopic Surveys

doi:10.3847/1538-4365/aa80e4

	The Ages and Masses of a Million Galactic-disk Main-sequence Turnoff and Subgiant Stars from the LAMOST Galactic Spectroscopic Surveys
	Liu, Xiaowei 1,5; Xiang, Maosheng 2; Huang, Yang 1; Chen, Bingqiu 1; Wang, Chun 1; Tian, Zhijia 1; Wu, Yaqian 3; Yang, Yong 1,3; Zhang, Huawei 1; Huo, Zhiying2
刊名	ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
	2017-09-01
卷号	232 期号:1
关键词	Catalogs Galaxy: Abundances Galaxy: Disk Galaxy: Evolution Stars: Fundamental Parameters Techniques: Spectroscopic
DOI	10.3847/1538-4365/aa80e4
文献子类	Article
英文摘要	We present estimates of stellar age and mass for 0.93 million Galactic-disk main-sequence turnoff and subgiant stars from the LAMOST Galactic Spectroscopic Surveys. The ages and masses are determined by matching with stellar isochrones using a Bayesian algorithm, utilizing effective temperature T-eff, absolute magnitude M-V, metallicity [Fe/H], and alpha-element to iron abundance ratio [alpha/Fe] deduced from the LAMOST spectra. Extensive examinations suggest the age and mass estimates are robust. Overall, the sample stars have a median error of 34% for the age estimates, and half of the stars older than 2 Gyr have age uncertainties of only 20%-30%. The median error for the mass estimates of the whole sample of stars is similar to 8%. The huge data set demonstrates good correlations among stellar age, [Fe/H] ([alpha/H]), and [alpha/Fe]. Particularly, double-sequence features are revealed in both the age-[alpha/Fe] and age-[Fe/H]([alpha/H]) spaces. In the [Fe/H]-[alpha/Fe] space, stars of 8-10 Gyr exhibit both the thin and thick disk sequences, while younger (older) stars show only the thin (thick) disk sequence, indicating that the thin disk became prominent 8-10 Gyr ago, while the thick disk formed earlier and was almost quenched 8 Gyr ago. Stellar ages exhibit positive vertical and negative radial gradients across the disk, and the outer disk of R greater than or similar to 9 kpc exhibits a strong flare in stellar age distribution.
WOS关键词	OLD OPEN CLUSTERS ; STELLAR ATMOSPHERIC PARAMETERS ; F-DWARF ; PHOTOMETRIC SYSTEMS ; NITROGEN ABUNDANCES ; CHEMICAL EVOLUTION ; FLUX CALIBRATION ; BLUE STRAGGLERS ; NEARBY STARS ; DATA RELEASE
WOS研究方向	Astronomy & Astrophysics
语种	英语
WOS记录号	WOS:000408442500002
资助机构	Joint Funds of the National Natural Science Foundation of China(U1531244) ; Joint Funds of the National Natural Science Foundation of China(U1531244) ; National Key Basic Research Program of China(2014CB845700) ; National Key Basic Research Program of China(2014CB845700) ; National Natural Science Foundation of China (NSFC)(11403038) ; National Natural Science Foundation of China (NSFC)(11403038) ; NSFC(11443006 ; NSFC(11443006 ; Beijing Normal University(310232102) ; Beijing Normal University(310232102) ; Special Funding for Advanced Users, budgeted ; Special Funding for Advanced Users, budgeted ; National Development and Reform Commission ; National Development and Reform Commission ; 11603002) ; 11603002) ; Joint Funds of the National Natural Science Foundation of China(U1531244) ; Joint Funds of the National Natural Science Foundation of China(U1531244) ; National Key Basic Research Program of China(2014CB845700) ; National Key Basic Research Program of China(2014CB845700) ; National Natural Science Foundation of China (NSFC)(11403038) ; National Natural Science Foundation of China (NSFC)(11403038) ; NSFC(11443006 ; NSFC(11443006 ; Beijing Normal University(310232102) ; Beijing Normal University(310232102) ; Special Funding for Advanced Users, budgeted ; Special Funding for Advanced Users, budgeted ; National Development and Reform Commission ; National Development and Reform Commission ; 11603002) ; 11603002)
内容类型	期刊论文
源URL	[http://ir.bao.ac.cn/handle/114a11/20130]
专题	国家天文台_光学天文研究部
作者单位	1.Peking Univ, Dept Astron, Beijing 100871, Peoples R China 2.Chinese Acad Sci, Natl Astron Observ, Key Lab Opt Astron, Beijing 100012, Peoples R China 3.Beijing Normal Univ, Dept Astron, Beijing 100875, Peoples R China 4.Univ Chinese Acad Sci, Beijing 100049, Peoples R China 5.Peking Univ, Kavli Inst Astron & Astrophys, Beijing 100871, Peoples R China
推荐引用方式 GB/T 7714	Liu, Xiaowei,Xiang, Maosheng,Huang, Yang,et al. The Ages and Masses of a Million Galactic-disk Main-sequence Turnoff and Subgiant Stars from the LAMOST Galactic Spectroscopic Surveys[J]. ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES,2017,232(1).
APA	Liu, Xiaowei.,Xiang, Maosheng.,Huang, Yang.,Chen, Bingqiu.,Wang, Chun.,...&Yuan, Haibo.(2017).The Ages and Masses of a Million Galactic-disk Main-sequence Turnoff and Subgiant Stars from the LAMOST Galactic Spectroscopic Surveys.ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES,232(1).
MLA	Liu, Xiaowei,et al."The Ages and Masses of a Million Galactic-disk Main-sequence Turnoff and Subgiant Stars from the LAMOST Galactic Spectroscopic Surveys".ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES 232.1(2017).