Fastest Star S301 Detected Near Milky Way’s Central Black Hole

A newly identified star, designated S301, has been observed orbiting the supermassive black hole at the center of the Milky Way with an unprecedented combination of speed and proximity. Astronomers using the Very Large Telescope’s GRAVITY instrument measured S301’s velocity to exceed 4,000 km s⁻¹, making it the fastest star ever recorded in the galactic core. Its pericenter distance— the closest point in its orbit to the black hole— is only about 1.8 astronomical units, roughly the orbital radius of Mars, placing it far closer to the event horizon than any previously known star.

The star’s extreme trajectory offers a unique laboratory for testing Einstein’s theory of general relativity under conditions of intense gravitational fields. By tracking the minute relativistic effects on S301’s orbit, scientists can probe the spacetime curvature around a supermassive black hole with unprecedented precision. Preliminary data already suggest a measurable gravitational redshift and precession consistent with relativistic predictions, while future observations aim to refine these measurements and potentially uncover deviations that could hint at new physics. The discovery of S301 thus opens a promising avenue for probing the fundamental nature of gravity in the most extreme environments.