Astronomers have discovered S301, the fastest star in the Milky Way, which travels around the central supermassive black hole Sagittarius A* at 25,000 kilometres per second.
The star moves roughly 100,000 times faster than a commercial airliner and is the closest known stellar body to Sagittarius A*, according to a report by The Guardian.
Orbit around Sagittarius A*
Felix Mang, a postgraduate researcher at the Max Planck Institute for Extraterrestrial Physics in Garching, Germany, said the star is unique because it follows an exceptionally tight path around the black hole. He noted that S301 completes a full orbit in just 8.7 years and comes within a distance 12 times that between Earth and the Sun, calling the close approach unprecedented.
The Max Planck Institute for Extraterrestrial Physics is a research facility located near Munich. Sagittarius A* is the supermassive black hole situated at the gravitational center of the Milky Way galaxy.
Testing Einstein's theory of relativity
The discovery provides astronomers with a new method to study the central black hole. Albert Einstein's general theory of relativity predicts that a massive black hole drags space and time along with its rotation. This distortion is expected to gradually alter S301's orbit, with the changes becoming measurable in about a decade because the star approaches so close to Sagittarius A*.
Stefan Gillessen, a co-author of the study who is also based at the Max Planck Institute, said researchers will be able to directly measure the spin of a massive black hole for the first time, providing a key test of Einstein's theory.
Scientists have traced the orbit of S301 since 2017. By monitoring the star until its next closest approach in 2031, researchers hope to collect enough data to observe the predicted relativistic effects.
Previous exoplanet discovery
The finding follows another astronomical discovery involving exoplanets beyond our Solar System. Astronomers previously detected an atmosphere around LHS 1140b, a rocky planet orbiting a small, cold M-dwarf star roughly 50 light years from Earth.
