Scientists identify S301 as fastest star in Milky Way

S301 is a star in the Milky Way galaxy that has been identified as the fastest-moving star recorded on a secure orbit. The discovery was announced on 19 August 2026 in a study published in Nature.

S301 and its measured speed

S301 reaches a maximum speed of about 15,500 miles per second, or 25,000 kilometres per second. This speed is roughly 8% of the speed of light. The star follows a highly elliptical orbit around Sagittarius A”, the supermassive black hole at the centre of the Milky Way.

Orbit around Sagittarius A”

The orbit of S301 takes 8.7 years to complete. At its closest approach, the star passes within 12 astronomical units of Sagittarius A”, which is about 1.8 billion kilometres. Sagittarius A” has a mass of about 4.3 million solar masses.

Observation method and research team

The discovery used the European Southern Observatory’s Very Large Telescope Interferometer at the Paranal Observatory in Chile. Researchers tracked archival data of S301 back to 2017. The international team was led by K. Abd El Dayem of the Paris Observatory, with Felix Mang and Stefan Gillessen of the Max Planck Institute for Extraterrestrial Physics.

Important Facts for Exams

• The Milky Way galaxy contains Sagittarius A”, the supermassive black hole at its centre.
• An astronomical unit is the average distance between the Earth and the Sun, which is about 149.6 million kilometres.
• Frame dragging is a relativistic effect linked to rotating massive bodies in Einstein’s theory of general relativity.
• The GRAVITY collaboration is associated with high-precision observations of stars near Sagittarius A”.

Earlier record claim

A star named S4714 was reported in 2020 as a record-breaker with a speed of 24,000 kilometres per second. Later GRAVITY collaboration measurements did not reproduce those results, leaving S301 as the verified fastest star on a secure orbit.