Astronomers detect fastest known star in Milky Way

Key Points:

• Astronomers have discovered S301, the fastest known star in the Milky Way, orbiting the supermassive black hole Sagittarius A* at about 25,000 km/s, making a complete orbit in just 8.7 years.
• S301 is the closest known star to Sagittarius A*, approaching within a distance comparable to Saturn's orbit around the Sun, providing a unique opportunity to study the black hole's properties and surrounding environment.
• The star's tight, highly eccentric orbit may allow scientists to directly measure the spin of Sagittarius A* within the next decade, offering a critical test of Einstein’s general theory of relativity.
• Observations were conducted using the European Southern Observatory’s Very Large Telescope Interferometer in Chile, enabling precise tracking of S301’s orbit since 2017 and future monitoring through its next close approach in 2031.
• Experts highlight that this discovery is significant for understanding black hole dynamics and the Milky Way’s evolution, as S301 travels at about 8% of the speed of light without crossing the black hole’s event horizon.