IC 4651

IC 4651是一个位于天坛座，距离地球约2900光年的疏散星团，最早由约翰·路易斯·埃米尔·德雷尔在他的1895年版NGC天体表中记录^[4]。

IC 4651
Wide Field Imager (WFI) camera拍摄到的疏散星团IC 4651，利用欧洲南方天文台在智利拉西亚天文台的MPG/ESO 2.2米望远镜。[1]
观测数据 (J2000 历元)
星座	天坛座
赤经	17h 24m 49s[2]
赤纬	−49° 56′ 00″[2]
距离	2,900 ly (888[3] pc)
视直径 (V)	10.0' (角分)
物理性质
其他名称（标示）	Melotte 169
相关条目：疏散星团、疏散星团列表

IC 4651的年龄大约为1.2±0.2亿年，属于中等年龄的星团^[5]。 与太阳相比，该星团中的恒星具有更高的化学元素丰度（氢和氦除外）^[6]。

IC 4651中活动恒星的总质量约为630个太阳质量^[7]。目前已知的活动恒星的质量只占星团初始质量的约7%。剩余质量中约35%演化成了白矮星或其他致密星。其余丢失质量组成的恒星星已经离开了星团主体或完全离开星团^[7]。

参考资料

1. Sibling Stars. [19 August 2015]. （原始内容存档于2017-12-27）.
2. Xin, Y.; Deng, L. Blue Stragglers in Galactic Open Clusters and Integrated Spectral Energy Distributions. The Astrophysical Journal. February 2005, 619 (2): 824–838. Bibcode:2005ApJ...619..824X. arXiv:astro-ph/0410325 . doi:10.1086/426681.
3. Dias, W.S.; Alessi, B.S.; Moitinho, A.; Lepine. J.R.D. New catalog of optically visible open clusters and candidates. Astronomy and Astrophysics. July 2002, 389: 871–873. Bibcode:2002A&A...389..871D. arXiv:astro-ph/0203351 . doi:10.1051/0004-6361:20020668. Note: see the VizieR catalogue B/ocl （页面存档备份，存于互联网档案馆）.
4. Dreyer, J. L. E. Index Catalogue of Nebulae found in the years 1888 to 1894, with Notes and Corrections to the New General Catalogue. Memoirs of the Royal Astronomical Society. 1895, 51: 185–228. Bibcode:1895MmRAS..51..185D.
5. Biazzo, K.; et al. Deriving temperature, mass, and age of evolved stars from high-resolution spectra. Application to field stars and the open cluster IC 4651. Astronomy and Astrophysics. December 2007, 475 (3): 981–989. Bibcode:2007A&A...475..981B. arXiv:0704.3192 . doi:10.1051/0004-6361:20077374.
6. Pasquini, L.; et al. Detailed chemical composition of the open cluster IC 4651: The iron peak, α elements, and Li. Astronomy and Astrophysics. September 2004, 424: 951–963. Bibcode:2004A&A...424..951P. arXiv:astro-ph/0406113 . doi:10.1051/0004-6361:20040240. This source gives a metallicity value of ${\displaystyle {\begin{smallmatrix}\left[{\frac {Fe}{H}}\right]\ =\ +0.10\ \pm \ 0.03\end{smallmatrix}}}$, which is equivalent to 125% of the Sun's abundance of Iron.
7. Meibom, S.; Andersen, J.; Nordström, B. Critical tests of stellar evolution in open clusters. III. Stellar population and dynamical evolution of IC 4651. Astronomy and Astrophysics. April 2002, 386: 187–203. Bibcode:2002A&A...386..187M. doi:10.1051/0004-6361:20020183.