泰尔让7
泰尔让7是松散和年轻的球状星团，被认为起源于人马座矮椭球星系（Sag DEG）并与之有物理上的关联。相较之下它是富金属，它的金属量是[Fe/H] = -0.6[6]，并且估计年龄是75亿岁[4]。泰尔让7有少量的镍（[Ni/Fe]=-0.2），因为有著相似的化学特征，这支持它是人马座矮椭球星系的成员[7]。它有丰富的蓝掉队星，并且强烈的朝向中心集中[8]。它的平均亮度分布在Mv = -5.05.[9]。它的半光度半径（Rh）= 6.5秒差距[10]。
| 泰尔让7 | |
|---|---|
 | |
| 观测数据(J2000 历元) | |
| 星座 | 人马座 |
| 赤经 | 19h 17m 43.92s[1] |
| 赤纬 | -34° 39′ 27.8″[1] |
| 距离 | 75.7 kly（23.2 kpc）[2] |
| 视星等 (V) | 12.0[2] |
| 视直径(V) | 7′.3[2] |
| 物理性质 | |
| 半径 | 160 光年[a] |
| VHB | 17.76[3] |
| 估计年龄 | 7.5 Gyr[4] |
| 值得注意的特色 | young extragalactic globular |
| 其它名称 | Ter 7,[4] GCl 109.1[5] |
历史
年轻的球状星团
几乎所有的银河系的银晕的球状星团是同时形成（12-15 Gyr）。 即使是位于远处的NGC 2419（距离银河中心约100 kpc）也有相似的年龄。这种趋势也适用于大麦哲伦星系和天炉座矮星系（来自银河中心的约140 kpc）发现的球状团的年龄。
注解
- ^ 75.7 kly × tan( 7′.3 / 2 ) = 160 ly. radius
参考资料
- ^ 1.0 1.1 Goldsbury, Ryan; et al, The ACS Survey of Galactic Globular Clusters. X. New Determinations of Centers for 65 Clusters, The Astronomical Journal, December 2010, 140 (6): 1830–1837, Bibcode:2010AJ....140.1830G, arXiv:1008.2755
, doi:10.1088/0004-6256/140/6/1830.
- ^ 2.0 2.1 2.2 Terzan 7 @ seds, （原始内容存档于2002-10-24）
- ^ Wilson, Barbara, Obscure Globulars, July 2, 1995 [2016-01-23], （原始内容存档于2016-01-13）
- ^ 4.0 4.1 4.2 Geisler, Doug; Wallerstein, George; Smith, Verne V.; Casetti-Dinescu, Dana I., Chemical Abundances and Kinematics in Globular Clusters and Local Group Dwarf Galaxies and Their Implications for Formation Theories of the Galactic Halo, The Publications of the Astronomical Society of the Pacific, September 2007, 119 (859): 939–961, Bibcode:2007PASP..119..939G, arXiv:0708.0570 , doi:10.1086/521990
- ^ SIMBAD Astronomical Object Database. Results for Terzan 7. [2008-01-27]. （原始内容存档于2020-05-17）.
- ^ Sbordone, L.; Bonifacio, P.; Marconi, G.; Buonanno, R.; Zaggia, S., Family ties: Abundances in Terzan 7, a Sgr dSph globular cluster, Astronomy and Astrophysics, July 3, 2005, 437 (3): 905–910, Bibcode:2005A&A...437..905S, arXiv:astro-ph/0505307 , doi:10.1051/0004-6361:20042315
- ^ Sbordone, L.; Bonifacio, P.; Marconi, G.; Buonanno, R., Chemical abundances in Terzan 7, Memorie della Societa Astronomica Italiana, 2004, 75: 396, Bibcode:2004MmSAI..75..396S
- ^ Held, Enrico V.; Rosenberg, Alfred; Saviane, Ivo; Momany, Yazan, 写于Pucon, Chile, Geisler, D.; Grebel, E.K.; Minniti, D. , 编, The Globular Cluster Terzan 7 in the Sagittarius Dwarf Spheroidal Galaxy, Astronomical Society of the Pacific (San Francisco), March 12–16, 2001: 165 (2002), Bibcode:2002IAUS..207..165H
- ^ van den Bergh, Sidney, The Luminosity Distribution of Globular Clusters in Dwarf Galaxies, The Astronomical Journal, July 2007, 134 (1): 344–345, Bibcode:2007AJ....134..344V, arXiv:0704.2226 , doi:10.1086/518868
- ^ van den Bergh, Sidney, Young Globular Clusters and Dwarf Spheroidals, The Astrophysical Journal, February 2000, 530 (2): 777–782, Bibcode:2000ApJ...530..777V, arXiv:astro-ph/9910243 , doi:10.1086/308413
- ^ Terzan, Agop, Six nouveaux amas stellaires (Terzan 3-8) dans la region DU centre de la Voie lactee et les constellations DU Scorpion et DU Sagittaire, C.R. Acad. Sci., 1968, 267 (Ser. B): 1245–1248, Bibcode:1968CRASB.267.1245T
- ^ 12.0 12.1 Gottlieb, Steve, Sky and Telescope, August 1, 2000, 100 (2): 112, ISSN 0037-6604 缺少或
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