Star S301 Challenges General Relativity at Galactic Core

• Astronomers have discovered S301, a star orbiting the supermassive black hole Sag A* with a period of only 8.7 years, making it the most relativistic star known.
• The star reaches speeds exceeding 8% of the speed of light, providing a unique natural laboratory to test the limits of general relativity.
• Unlike the subtle orbital precession observed in Mercury, S301’s perihelion advances by roughly 2° per orbit, enabling the study of extreme gravitational effects.

Scientific Significance

• S301 exhibits extreme relativistic effects, including significant orbital precession, gravitational redshift, and transverse Doppler effects.
• Researchers aim to use the star to distinguish between general relativity and alternative gravity models that attempt to reconcile gravity with quantum theory.
• Observations will focus on second- and third-order effects related to the black hole’s spin and its interaction with the star’s rotation.

Observational Challenges

• The galactic center is obscured by thick clouds of dust and gas, preventing optical observations.
• S301 is a Sun-like star with low luminosity, even in infrared, limiting current spectral data acquisition.
• Future high-precision instruments, such as the Giant Magellan Telescope (GMT), are required to fully capture the spectral data necessary to measure these high-order relativistic effects.