半人马座的球状奥米茄星团

半人马座的球状奥米茄星团

Globular Cluster Omega Centauri
Image Credit & Copyright: Juergen Stein

Explanation: Globular star cluster Omega Centauri packs about 10 million stars much older than the Sun into a volume some 150 light-years in diameter. Also known as NGC 5139, at a distance of 15,000 light-years 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. With a yellowish hue, Omega Centauri’s red giant stars are easy to pick out in this sharp telescopic view. A two-decade-long exploration of the dense star cluster with the Hubble Space Telescope has revealed evidence for a massive black hole near the center of Omega Centauri.

Tomorrow’s picture: pixels in space

半人马座的球状奥米茄星团
影像提供与版权: Juergen Stein

说明: 在球状的奥米茄星团里头，大约1千万颗远比太阳年老的恒星，拥挤在直径约150光年的体积之内。亦名为NGC 5139、离我们约15,000光年远的这个星团，是在我们银河系银晕内漫游的200多个球状星团中，最大与最明亮的一个。在大多数的星团里，成员星具有相同的年龄和化学组成，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，奥米茄星团或许是一个小星系被我们的银河吞并后，所孑遗下来的星系核。在这幅清晰的望远镜彩色影像里，奥米茄星团泛黄的红巨星轻易可辨。此外，使用哈勃太空望远镜对这个致密星团进行了长达20年的探索之后，找到了奥米茄星团的中心附近有个大质量黑洞的证据。

明日的图片: pixels in space