Astronomers have discovered the fastest known star in the Milky Way
Astronomers have discovered the fastest known star in the Milky Way—a faint object designated S301, which orbits the supermassive black hole Sagittarius A* at the center of the galaxy. At the fastest point in its orbit, the star moves at a speed of about 25,000 kilometers per second, or more than 8% of the speed of light, according to Space.com.
S301 completes one full orbit around Sagittarius A* in 8.7 years. During its closest approach, it comes within a distance approximately 12 times greater than the distance between Earth and the Sun. According to the study’s author, Felix Manga, a doctoral candidate at the Max Planck Institute for Extraterrestrial Physics, such a close orbit is unprecedented.
The star was discovered in 2023 using the GRAVITY instrument on the European Southern Observatory’s Very Large Telescope Interferometer in Chile. The researchers then traced it back to observations made in 2021 and 2017.
For more breaking news, follow the UA.News Telegram channel.
S301’s highly elongated orbit may indicate that it was previously part of a binary star system that came too close to Sagittarius A*. The researchers hypothesize that the black hole may have captured S301 while ejecting its companion at high speed.
Further observations may help directly measure the rotation of the black hole, which has a mass of approximately 4.3 million solar masses. According to general relativity, a rotating black hole drags spacetime along with its motion, which should gradually alter S301’s orbit. The star’s next close pass is expected in 2031. Astronomers plan to continue observations using GRAVITY+ and ESO’s Extremely Large Telescope. The results of the study were published on August 19 in the journal *Nature*.
