Dancing on the edge of a black hole: Meet S301

GRAVITY+ at ESO’s Very Large Telescope Interferometer has discovered S301, a star about two billion times fainter than Betelgeuse on an extreme orbit around Sagittarius A*, the supermassive black hole at the centre of the Milky Way. At closest approach it comes within roughly the Sun–Saturn distance of the black hole and moves at nearly 8% of the speed of light. Its path is sensitive to Lense–Thirring frame-dragging, so further observations may provide the first direct measurement of how fast the Galaxy’s central black hole is spinning. Researchers from the KU Leuven Institute of Astronomy are co-authors of the Nature paper.