奥米茄星团

2024年3月28日

Millions of Stars in Omega Centauri
Image Credit & Copyright: Massimo Di Fusco and Mirco Turra

Explanation: Globular star cluster Omega Centauri, also known as NGC 5139, is 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. With a yellowish hue, Omega Centauri’s red giant stars are easy to pick out in this sharp, color telescopic view.

Tomorrow’s picture: Galileo’s Europa

奥米茄星团
影像提供与版权: Massimo Di Fusco and Mirco Turra

说明: 半人马座的奥米茄球状星团（NGC 5139），离我们约有15,000光年远。在这个星团里，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。于我们银河系银晕内漫游的200多个球状星团中，它是最大与最明亮者。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。

明日的图片: Galileo’s Europa