Discovery of high-velocity EHB stars in the globular cluster omega Centauri (NGC 5139)
文献类型：期刊论文
| 作者 | Gao, Xin-Hua1; Xu, Shou-Kun1; Chen, Li2
|
| 刊名 | RESEARCH IN ASTRONOMY AND ASTROPHYSICS
 |
| 出版日期 | 2015-10-01 |
| 卷号 | 15期号:10页码:1639-1646 |
| 关键词 | Galaxy: globular clusters: individual: omega Cen (NGC 5139) stars: Hertzsprung-Russell and C-M diagrams stars: kinematics and dynamics stars: binaries (including multiple): close |
| 英文摘要 | We report the discovery of 45 high-velocity extreme horizontal branch (EHB) stars in the globular cluster Omega Centauri (NGC 5139). The tangential velocities of these EHB stars are determined to be in the range 93 similar to 313 km s(-1), with an average uncertainty of similar to 27 km s(-1). The central escape velocity of the cluster is determined to be in the range 60 similar to 105 km s(-1). These EHB stars are significantly more concentrated toward the cluster core compared with other cluster members. The formation mechanisms of these EHB stars are discussed. Our conclusions can be summarized as follows: (1) A comparison of the tangential velocities of these EHB stars to the central escape velocity of the cluster shows that most if not all of these EHB stars are unbound to the cluster; (2) These EHB stars obtained high velocities in the central cluster region no longer than similar to 1 Myr ago and may be subsequently ejected from the cluster in the next similar to 1 Myr; (3) If the progenitors of these EHB stars were single stars, then they may have experienced a fast mass-loss process. If the progenitors were in close binaries, then they may have formed through disruptions by the intermediate-mass black hole in the cluster center. |
| WOS标题词 | Science & Technology ; Physical Sciences |
| 类目[WOS] | Astronomy & Astrophysics |
| 研究领域[WOS] | Astronomy & Astrophysics |
| 关键词[WOS] | HORIZONTAL-BRANCH STARS ; SUBDWARF-B STARS ; MASS BLACK-HOLE ; BINARY FRACTION ; ELLIPTIC GALAXIES ; CLOSE BINARIES ; MILKY-WAY ; SDB STARS ; UV-UPTURN ; HOT |
| 收录类别 | SCI |
| 语种 | 英语 |
| WOS记录号 | WOS:000362825700003 |
| 源URL | [http://119.78.226.72/handle/331011/28375]  |
| 专题 | 上海天文台_星系宇宙学重点实验室 |
| 作者单位 | 1.Changzhou Univ, Sch Informat Sci & Engn, Changzhou 213164, Peoples R China 2.Chinese Acad Sci, Shanghai Astron Observ, Shanghai 200030, Peoples R China |
| 推荐引用方式 GB/T 7714 | Gao, Xin-Hua,Xu, Shou-Kun,Chen, Li. Discovery of high-velocity EHB stars in the globular cluster omega Centauri (NGC 5139)[J]. RESEARCH IN ASTRONOMY AND ASTROPHYSICS,2015,15(10):1639-1646. |
| APA | Gao, Xin-Hua,Xu, Shou-Kun,&Chen, Li.(2015).Discovery of high-velocity EHB stars in the globular cluster omega Centauri (NGC 5139).RESEARCH IN ASTRONOMY AND ASTROPHYSICS,15(10),1639-1646. |
| MLA | Gao, Xin-Hua,et al."Discovery of high-velocity EHB stars in the globular cluster omega Centauri (NGC 5139)".RESEARCH IN ASTRONOMY AND ASTROPHYSICS 15.10(2015):1639-1646. |
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来源：上海天文台
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