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相关论文: The Blue Horizontal-Branch Stars From the LAMOST S…

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Massive stars play key roles in many astrophysical processes. Deriving atmospheric parameters of massive stars is important to understand their physical properties and thus are key inputs to trace their evolution. Here we report our work on…

太阳与恒星天体物理 · 物理学 2021-12-15 YanJun Guo , Bo Zhang , Chao Liu , Jiao Li , JiangDan Li , LuQian Wang , ZhiCun Liu , YongHui Hou , ZhanWen Han , XueFei Chen

We construct a new catalog of the blue horizontal-branch (BHB) stars from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) DR5 dataset, which contains 5355+81 BHB stars at high Galactic latitude (($|Glat|>20^{\circ}$).…

星系天体物理 · 物理学 2023-11-29 Jie Ju , Wenyuan Cui , Zhenyan Huo , Chao liu , Xiangxiang Xue , Jiaming Liu , Shuai Feng , Mingxu Sun , Linlin Li

We collect a sample of stars observed both in LAMOST and Gaia which have colors implying a temperature hotter than 7000 K. We train a machine learning algorithm on LAMOST spectroscopic data which has been tagged with stellar classifications…

星系天体物理 · 物理学 2021-05-12 John J. Vickers , Zhao-Yu Li , Martin C. Smith , Juntai Shen

The stars within our Galactic halo presents a snapshot of its ongoing growth and evolution, probing galaxy formation directly. Here, we present our first analysis of the stellar halo from detailed maps of Blue Horizontal Branch (BHB) stars…

星系天体物理 · 物理学 2018-08-01 Zhen Wan , Prajwal R. Kafle , Geraint F. Lewis , Dougal Mackey , Sanjib Sharma , Rodrigo A. Ibata

We derive stellar parameters and abundances (`stellar labels') of 40,034 late-B and A-type main-sequence stars extracted from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope Medium Resolution Survey (LAMOST--MRS). The primary…

太阳与恒星天体物理 · 物理学 2021-11-17 Weijia Sun , Xiao-Wei Duan , Licai Deng , Richard de Grijs , Bo Zhang , Chao Liu

Blue horizontal-branch (BHB) stars are old, low-mass, metal-poor stars that serve as important tracers of the Galactic halo structure, kinematics, and evolution.Understanding their binary properties provides key insights into their…

太阳与恒星天体物理 · 物理学 2025-10-01 Yanjun Guo , Kun Chen , Zhenwei Li , Jie Ju , Chao Liu , Xiangxiang Xue , Matti Dorsch , Zhanwen Han , XueFei Chen

M dwarf stars are the most common stars in the Galaxy, dominating the population of the Galaxy by numbers at faint magnitudes. Precise and accurate stellar parameters for M dwarfs are of crucial importance for many studies. However, the…

太阳与恒星天体物理 · 物理学 2021-04-21 Jiadong Li , Chao Liu , Bo Zhang , Hao Tian , Dan Qiu , Haijun Tian

This paper investigates the problem of estimating three stellar atmospheric physical parameters and thirteen elemental abundances for medium-resolution spectra from Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). Typical…

太阳与恒星天体物理 · 物理学 2023-12-27 Xiangru Li , Xiaoyu Zhang , Shengchun Xiong , Yulong Zheng , Hui Li

Blue horizontal-branch (BHB) stars are ideal tracers for mapping the structure of Galactic stellar halo. Traditionally, BHB sample stars are built from large-scale spectroscopic surveys utilizing their spectral features, however, the…

Employing a new machine learning method, named hierarchical extreme learning machine (HELM) algorithm, we identified 56 hot subdwarf stars in the first data release (DR1) of the Large Sky Area Multi-Object Fibre Spectroscopic Telescope…

太阳与恒星天体物理 · 物理学 2019-07-02 Zhenxin Lei , Yude Bu , Jingkun Zhao , Péter Németh , Gang Zhao

Blue Horizontal Branch (BHB) stars, excellent distant tracers for probing the Milky Way's halo density profile, are distinguished in the $(g-r)_0$ vs $(i-z)_0$ color space from another class of stars, blue straggler stars (BSs). We develop…

We discuss a 175 deg^2 spectroscopic survey for blue horizontal branch (BHB) stars in the Galactic halo. We use the Two Micron All Sky Survey (2MASS) and the Sloan Digital Sky Survey (SDSS) to select BHB candidates, and find that the 2MASS…

We present the stellar density profile of the outer halo of the Galaxy traced over a range of Galactocentric radii from $15< R_{GC} < 220$ kpc by blue horizontal branch (BHB) stars. These stars are identified photometrically using deep…

We use Legacy Survey photometric data to probe the stellar halo in multiple directions of the sky using a probabilistic methodology to identify Blue Horizontal Branch (BHB) stars. The measured average radial density profile follows a double…

星系天体物理 · 物理学 2024-10-09 João A. S. Amarante , Sergey E. Koposov , Chervin F. P. Laporte

Ground-based optical surveys such as PanSTARRS, DES, and LSST, will produce large catalogs to limiting magnitudes of r > 24. Star-galaxy separation poses a major challenge to such surveys because galaxies---even very compact…

天体物理仪器与方法 · 物理学 2015-06-05 Ross Fadely , David W. Hogg , Beth Willman

The LAMOST survey has provided 9 million spectra in its Data Release 5 (DR5) at R$\sim$1800. Extracting precise stellar labels is crucial for such a large sample. In this paper, we report the implementation of the Stellar LAbel Machine…

太阳与恒星天体物理 · 物理学 2020-01-15 Bo Zhang , Chao Liu , Li-Cai Deng

We present VLT-FORS1 spectra of a sample of 34 faint 20.0 < g* < 21.1 A-type stars selected from the Sloan Digital Sky Survey Early Data Release, with the goal of measuring the velocity dispersion of blue horizontal branch (BHB) stars in…

天体物理学 · 物理学 2008-11-26 L. Clewley , S. J. Warren , P. C. Hewett , John. E. Norris , M. I. Wilkinson , N. W. Evans

We present coordinates and available photometric information (either from previous or recent broadband UBV observations, and near-infrared photometry from the 2MASS Point Source Catalog) for 12056 stars (11516 of which are unique)…

天体物理学 · 物理学 2009-11-11 Timothy C. Beers , Tiago Almeida , Silvia Rossi , Ronald Wilhelm , Brian Marsteller

We use 2MASS photometry to select blue horizontal branch (BHB) candidates covering the sky |b|>15 deg. A 12.5<J<15.5 sample of BHB stars traces the thick disk and inner halo to d<9 kpc, with a density comparable to that of M giant stars. We…

天体物理学 · 物理学 2015-06-24 Warren R. Brown , M. J. Geller , S. J. Kenyon , T. C. Beers , M. J. Kurtz , J. B. Roll

The effects of blue horizontal-branch (HB) stars on the integrated spectrophotometric indices of simple stellar populations (SSPs) are addressed. Synthetic spectra are drawn from a grid of simulated globular clusters, constructed so as to…

天体物理学 · 物理学 2009-11-07 Hyun-chul Lee , Young-Wook Lee , Brad K. Gibson
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