VLTI Detects S-Cluster Star S301 with Orbital Velocity Reaching 25,000 km/s Near Sagittarius A*
Astronomers utilized the European Southern Observatory's Very Large Telescope Interferometer (ESO's VLTI) to track the orbit of the newly identified star S301 near the Galactic Center. Astrometric measurements reveal the star reaches velocities up to 25,000 km/s during its close periastron passage around the four-million-solar-mass supermassive black hole. The orbit brings S301 closer than previously cataloged S-stars, placing it into a regime governed by strong-field general relativistic effects.
Characterizing the orbit as 'feeling the black hole's spin' refers to subtle general relativistic frame-dragging (Lense-Thirring precession) rather than any physical contact or impending destruction. Measuring these spin-induced orbital perturbations requires sustained astrometric tracking over multiple orbits to untangle relativistic effects from perturbations caused by any distributed dark mass or fainter stellar remnants. The star remains well outside the black hole's event horizon and tidal disruption radius, continuing along a stable ballistic orbit.