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Fastest Known Star S301 Confirmed Orbiting Sagittarius A*

8/19/2026

Summary

Story summary

Chile astronomers using ESO’s Very Large Telescope Interferometer detected star S301 orbiting Sagittarius A*.
S301 travels at about 25,000 km per second—roughly 8 % of light speed—making it the fastest known star.
The star completes an 8.7-year orbit, reaching within 11.5 astronomical units of the black hole at closest approach.
Researchers Felix Mang and Stefan Gillessen will monitor S301 through its 2031 close passage to directly measure Sagittarius A*’s spin.

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Story summary

Chile astronomers using ESO’s Very Large Telescope Interferometer detected star S301 orbiting Sagittarius A*.
S301 travels at about 25,000 km per second—roughly 8 % of light speed—making it the fastest known star.
The star completes an 8.7-year orbit, reaching within 11.5 astronomical units of the black hole at closest approach.
Researchers Felix Mang and Stefan Gillessen will monitor S301 through its 2031 close passage to directly measure Sagittarius A*’s spin.