Scientists identify S301 as fastest star in Milky Way

Key facts

• Astronomers discovered the fastest known star in the Milky Way, designated S301, which orbits the supermassive black hole Sagittarius A
• .
• S301 reaches speeds of about 15,500 miles per second (25,000 kilometers per second), exceeding 8% of the speed of light.
• The star completes an orbit around Sagittarius A
• in just 8.7 years, approaching within 12 times the Earth-Sun distance.
• The discovery was made using the GRAVITY instrument on the European Southern Observatory's Very Large Telescope Interferometer in Chile.
• S301 was traced back through observations from 2021 and 2017, and its highly elongated orbit suggests it may have been captured from a binary system.
• The next close pass of S301 is expected in 2031, and observations spanning two full orbits could measure the black hole's spin via frame dragging.
• The research was published in the journal Nature on August 19.