M2
影像来源与版权:ESA/Hubble & NASA, G. Piotto et al.

说明:继蟹状星云M1之后,这个巨大的星团是18世纪天文学家查尔斯·梅西耶编录的著名非彗星星表中的第二个天体。M2是目前已知的、漫游在银河系光环上的最大球状星团之一。虽然梅西耶最初将它描述为一个没有恒星的星云,但是这幅精美的哈勃影像呈现了M2中央40光年区域内的恒星。它的恒星数量接近15万颗,集中在总直径约175光年的区域内。这个古老的银河系居民位于水瓶座方向、距离我们约55,000光年远处,它也被称为NGC7089,年龄有130亿年。
翻译:北京天文馆

Messier 2
Image Credit & Copyright: ESA/Hubble & NASA, G. Piotto et al.

Explanation: After the Crab Nebula, M1, this giant star cluster is the second entry in 18th century astronomer Charles Messier’s famous list of things that are not comets. M2 is one of the largest globular star clusters now known to roam the halo of our Milky Way galaxy. Though Messier originally described it as a nebula without stars, this stunning Hubble image resolves stars across the central 40 light-years of M2. Its population of stars numbers close to 150,000, concentrated within a total diameter of around 175 light-years. About 55,000 light-years distant toward the constellation Aquarius, this ancient denizen of the Milky Way, also known as NGC 7089, is 13 billion years old.
Astronomy Picture of the Day 04/04/2019