Short answer first: astronomers have confirmed that young, massive stars orbiting close to Sagittarius A*, the black hole at the center of our own galaxy, are much less likely to have a companion star than identical stars anywhere else in the Milky Way. Computer simulations now point to the black hole's own gravity as the culprit.
Who lives that close to a black hole?
The stars in question form the so-called S-cluster: a swarm of young B-type stars, only a few million years old on average, packed into the innermost region around Sagittarius A, roughly 0.04 parsecs from it — about 8,000 times the distance between Earth and the Sun. Sagittarius A itself is a supermassive black hole weighing in at around 4 million times the mass of the Sun, sitting at the exact center of the Milky Way. Just being young and massive that close to a black hole is already strange; most stars form in the calmer, less crowded outskirts of galaxies.
A binary fraction that doesn't add up
Most massive stars are born with a partner. Across the general population of massive stars scattered through the galaxy, about 69% (±9%) come in binary pairs. Among the young S-cluster stars circling Sagittarius A*, that number drops to just 43% (±9%). That's not a small statistical wobble — it's a gap wide enough to demand an explanation, especially since these stars are too young to have simply drifted in from somewhere else after losing a partner along the way.
What the simulations found
A team led by Rodrigo P. Silva at the University of Coimbra, in a study published in Astronomy & Astrophysics on August 11, 2026, built a computer model tracking 100,000 simulated binary star systems for one million years, using orbital parameters that match the real structure of the S-cluster. The result: 62% of the simulated binaries survived intact, 18% merged into a single star, and 20% were torn apart entirely — producing a final binary fraction of about 38% (±10%). That number lines up closely with what's actually observed, which is a strong sign the simulation is capturing the right physics.
Born on the edge, not exiled there
The study favors in-situ formation — meaning these stars were born right where they are now, out of gas that fragmented and collapsed close to the black hole, rather than forming elsewhere as ordinary binaries and later migrating inward. What breaks up their companionships isn't distance traveled; it's tidal disruption that grows stronger the closer a system sits to Sagittarius A*. A black hole with millions of times the Sun's mass pulls harder on the near side of a binary pair than the far side, and close to the center that stretching force is strong enough to strip a star of its partner outright, or force the pair to merge before the disruption finishes the job.
A gentler version of the same idea, closer to home
Our own solar system runs on the same physics, just at a survivable scale. Tidal forces are the reason Jupiter's moon Io is the most volcanically active body in the solar system — squeezed and flexed by Jupiter's gravity on every orbit — and one leading idea for the origin of Saturn's rings is a moon that wandered inside the planet's Roche limit and was pulled apart rather than merely disrupted. Nothing in our solar system approaches the tidal violence near a supermassive black hole, but the underlying mechanism — gravity pulling harder on one side of an object than the other — is the exact same one now blamed for stripping stellar partners near the center of the galaxy.
See the mechanism, not just the numbers
Tidal effects are easy to describe in a sentence and hard to picture from text alone. On the real-time 3D simulator at Solar System Live, you can watch Io tucked in tight around Jupiter and see how differently gravity behaves at different distances from a massive body — a small, safe preview of the far more extreme tug-of-war now thought to be quietly dismantling binary stars 26,000 light-years away, at the heart of our own galaxy.