奥米茄星团

2019 August 24

Millions of Stars in Omega Centauri
Image Credit & Copyright: Michael Miller, Jimmy Walker

Explanation: Globular star cluster Omega Centauri, also known as NGC 5139, is some 15,000 light-years away. The cluster is packed with about 10 million stars much older than the Sun within a volume about 150 light-years in diameter. It’s the largest and brightest of 200 or so known globular clusters that roam the halo of our Milky Way galaxy. Though most star clusters consist of stars with the same age and composition, the enigmatic Omega Cen exhibits the presence of different stellar populations with a spread of ages and chemical abundances. In fact, Omega Cen may be the remnant core of a small galaxy merging with the Milky Way.

奥米茄星团
影像提供与版权: Michael Miller, Jimmy Walker

说明: 半人马座内的球形的奥米茄星团，又名为NGC 5139，离我们约有15,000光年远。在这个星团里，大约1千万颗比太阳年老的恒星，挤在直径约150光年的体积之内。而在我们银河系银晕内漫游的200多个球状星团中，它是最大与最明亮的一个。在大部份的星团里，成员星的年龄和化学组成皆很接近，然而谜样的奥米茄星团却有不同分群的恒星，各自拥有不同的年龄层和化学组成。因此，奥米茄星团可能是一个小星系被我们的银河并吞后，孑遗下来的星系核。