球状星团ngc6752
(原标题: Globular Star Cluster NGC 6752)
2024-10-25
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大约13000光年远的南方星座Pavo，球状星团NGC 6752漫步在我们银河系的光晕中。超过100亿年的历史，NGC 6752是继半人马座欧米茄星团、土人马座47星团和梅西耶22星团之后，地球夜空中第四亮的球状星团。它在一个直径约100光年的球体中容纳了超过10万颗恒星。对NGC 6752的望远镜探测发现，该星团核心附近的恒星中有相当一部分是多星系统。它们还揭示了蓝散星的存在，这些恒星看起来太年轻，质量太大，不可能存在于一个星团中，该星团的恒星年龄预计至少是太阳的两倍。蓝离散星被认为是在星团核心密集的恒星环境中由恒星合并和碰撞形成的。这种鲜明的颜色组合也使星团中古老的红巨星呈现出淡黄色。（注：距星团中心约8点钟方向的那颗明亮的、尖刺状的蓝色恒星是NGC 6752视线方向上的一颗前景恒星）
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Some 13,000 light-years away toward the southern constellation Pavo, the globular star cluster NGC 6752 roams the halo of our Milky Way galaxy. Over 10 billion years old, NGC 6752 follows clusters Omega Centauri, 47 Tucanae, and Messier 22 as the fourth brightest globular in planet Earth's night sky. It holds over 100 thousand stars in a sphere about 100 light-years in diameter. Telescopic explorations of NGC 6752 have found that a remarkable fraction of the stars near the cluster's core are multiple star systems. They also reveal the presence of blue straggle stars, stars which appear to be too young and massive to exist in a cluster whose stars are all expected to be at least twice as old as the Sun. The blue stragglers are thought to be formed by star mergers and collisions in the dense stellar environment at the cluster's core. This sharp color composite also features the cluster's ancient red giant stars in yellowish hues. (Note: The bright, spiky blue star about 8 o'clock from the cluster center is a foreground star along the line-of-sight to NGC 6752)
© Massimo Di Fusco