Astronomers have identified the fastest star ever recorded in the Milky Way, located near the supermassive black hole at the center of our galaxy. The star, designated S301, orbits Sagittarius A* with an orbital period of just 8.7 years. Its proximity to the black hole is significant because the intense gravitational environment allows researchers to observe effects predicted by Einstein's General Theory of Relativity.
S301 travels at a velocity of 25,000 kilometers per second and approaches the black hole within 12 astronomical units. This position is unique because the massive black hole drags and twists spacetime as it rotates. This phenomenon, known as the Lense-Thirring effect, causes the star's orbital path to shift in a way that researchers can measure over the next decade. By tracking these shifts, scientists aim to calculate the spin of the central black hole directly.
Finding S301 required a massive effort from the GRAVITY instrument team on the Very Large Telescope. The star is two billion times dimmer than Betelgeuse, making it difficult to spot. Since 2017, the team collected data for 100 hours annually, eventually confirming 19 distinct positions that map out the star's elliptical orbit. The discovery confirms that the star likely migrated to its current location after being separated from a binary partner by the gravitational forces of the black hole.
This discovery provides a faster timeline for testing spacetime physics than previously possible. Measuring the spin of Sagittarius A* would usually require decades of monitoring multiple stars. With S301, the team expects to complete these measurements within ten years. This work confirms details about how supermassive black holes influence the movement of nearby celestial bodies and provides a new method for verifying fundamental physical laws in extreme conditions.