Astronomers have identified the closest known star to the supermassive black hole at the center of the Milky Way, according to a report from Ars Technica. The finding, published this week, details a star that orbits Sagittarius A, the galaxy’s central black hole, at a distance closer than any previously observed stellar companion.
The discovery was made using data from multiple telescopes, Ars Technica reports. The star’s orbit brings it extremely near the black hole, allowing researchers to study gravitational effects in a region of space that has been difficult to observe directly. The star is sensitive to the spin of Sagittarius A, a property that could offer new clues about how the black hole rotates and how it influences its immediate surroundings.
The star is also notable for its speed. According to coverage from The Guardian and AP News, it is the fastest known star in the Milky Way, zipping around the black hole at a velocity that tests the limits of Einstein’s theory of general relativity. Popular Science notes that the star’s motion, measured at roughly 15,000 miles per second, provides a natural laboratory for checking whether relativity holds under extreme gravitational conditions.
This is not the first star found near Sagittarius A*, but it is the closest yet, Ars Technica reports. Previous discoveries have mapped a cluster of stars orbiting the black hole, but this new object pushes the boundary of what astronomers can detect, offering a sharper view of the space just outside the event horizon.
What to watch next: further observations of the star’s orbit could reveal whether its motion deviates from relativity predictions, potentially pointing to new physics.
