A star on the edge of a black hole
Astronomers have discovered a star orbiting the Milky Way's central black hole. The black hole is called Sagittarius A*. The star is named S301. It passes closer to the black hole than any known star. Its orbit is the tightest and most extreme ever recorded. The star is faint and was hard to spot. Researchers used the GRAVITY instrument at the Very Large Telescope Interferometer in Chile. The telescope combines light from four large telescopes. That gives it the sharpness needed to see stars near the black hole.
Why the orbit matters
The star's path is shaped by the black hole's gravity. The closer a star gets, the more its orbit twists. That twisting depends on how fast the black hole spins. A spinning black hole drags space around with it. Scientists call this effect frame dragging. By measuring S301's orbit in detail, researchers can estimate the spin. No one has measured the spin of Sagittarius A* before. The spin holds clues about how the black hole formed and grew.
What comes next
The team plans to track S301 over the coming years. More observations will refine the orbit measurements. The star takes years to complete one loop around the black hole. Scientists will also look for other stars on similar paths. Each new orbit adds to the picture of the galaxy's center. Understanding the black hole helps explain how the Milky Way evolved. The research was reported by the European Southern Observatory team.