Scientists find closest star to the Milky Way's central black hole

This leads to some pretty outrageous consequences. For example, at its closest approach, the star is moving at about 25,000 kilometers a second, which is over 8 percent of the speed of light. At this closest approach, the star passes 10 times closer to Sgr A* than the previously identified closest star. The researchers estimate that the distance may be as small as 11 Astronomical Units (one AU is the typical distance between the Earth and Sun). That would make the separation between the two just a bit beyond Saturn’s distance from the Sun. That’s close enough that, if S301 were a larger star (it appears to be about 1.5 times larger than the Sun), it would be disrupted by the gravity of the black hole. The researchers think that S301 got there by being part of a binary system that wandered too close to Sgr A*, with its partner having been ejected from the neighborhood of the black hole. But the more significant aspect of the discovery is what it could tell us in the future. The researchers estimate that we already have instruments that can track S301’s orbit with enough precision to provide an estimate of the spin of Sgr A* with about a decade of data. Further improvements in resolution or even a longer time series would let us start exploring even finer details of the supermassive black hole. These include whether it deviates from a perfect sphere, and whether the black hole has any additional properties beyond spin that influence its behavior. In short, finding S301 may be like developing a higher-precision instrument to study a supermassive black hole. Nature, 2026. DOI: 10.1038/s41586-026-10894-w (About DOIs).