天文学家利用哈伯与韦伯太空望远镜的数据，在半人马座ω星团中首次发现了一个恒星级黑洞，命名为 oMEGACat BH-2。这个星团理应存在约一万个此类黑洞，但过去的研究始终未能找到，这次的发现有助于完善星团内黑洞形成的相关理论。

研究团队采用了天体测量学的方法，分析了二十多年来的数据来追踪恒星的微小移动。他们发现一颗质量为0.78个太阳质量的可见恒星，正围绕著一个质量为4.46个太阳质量的不可见天体运行，由于质量过大而排除了中子星的可能性，确认其为黑洞。

这个黑洞与恒星组成的联星系统拥有长达94年的轨道周期，是目前已知周期最长的黑洞联星。其质量低于预期，且可能是在星团内动态形成的。这项发现不仅展现了哈伯数据的巨大价值，也为理解黑洞族群及其对重力波事件的影响提供了关键线索。

Astronomers have discovered the first stellar-mass black hole, named oMEGACat BH-2, in the Omega Centauri cluster using data from the Hubble and Webb space telescopes. While models suggest the cluster should contain about 10,000 such black holes, they had evaded detection in previous studies, and this discovery will help refine theories on black hole formation in such environments.

The research team used astrometry to analyze over two decades of data, tracking the tiny movements of stars. They found a visible star with 0.78 solar masses orbiting an invisible object with 4.46 solar masses, which is too massive to be a neutron star and thus confirmed to be a black hole.

This black hole and its companion star form a binary system with a 94-year orbital period, making it the longest-period black hole binary currently known. Its mass is lower than expected, and it likely formed dynamically within the cluster. This breakthrough highlights the immense value of archival Hubble data and provides crucial clues for understanding black hole populations and their impact on gravitational wave events.