S301: The Milky Way's Fastest Star Offers a Decade-Long Path to Measuring Black Hole Spin
Astronomers have identified S301, a faint star on the shortest known orbit around the Milky Way's central black hole, Sagittarius A*. With an 8.7-year period and pericentre speed exceeding 8% of light speed, S301 passes roughly ten times closer to the black hole than the previously known record holder, S2. While current data confirm general relativistic precession, the star's extreme proximity offers a unique opportunity to measure the black hole's spin within the next decade, provided future instruments achieve the required precision.
