Omega Centauri's First Stellar-Mass Black Hole Discovered by Hubble and Webb

Astronomers using more than 20 years of archival data from NASA's Hubble Space Telescope together with recent observations from the James Webb Space Telescope have identified the first stellar‑mass black hole in the massive globular cluster Omega Centauri. The object, designated oMEGACat BH‑2, has a measured mass of about 4.46 solar masses and orbits a visible 0.78‑solar‑mass companion star every 94 years – the longest orbital period known for any black‑hole binary. Lead author Matthew Whitaker said, "The precision of these measurements is incredible, down to a fraction of a pixel on Hubble and Webb’s detectors." The discovery, published in *The Astrophysical Journal Letters* on 13 July 2026, refines models of black‑hole formation in metal‑poor environments and overturns an earlier suggestion that the companion was a neutron star. The study was led by researchers at the University of Utah, including co‑author Anil Seth, and highlights the combined power of Hubble and Webb for astrometric investigations.