GALACTIC-CENTER S STARS AS A PROSPECTIVE TEST OF THE EINSTEIN EQUIVALENCE PRINCIPLE
- Institute for Theoretical Physics, University of Zuerich, Winterthurerstrasse 190, CH-8057 Zuerich (Switzerland)
The S stars in the Galactic-center region are found to be on near-perfect Keplerian orbits around presumably a supermassive black hole, with periods of 15-50 yr. Since these stars reach a few percent of light speed at pericenter, various relativistic effects are expected and have been discussed in the literature. We argue that an elegant test of the Einstein equivalence principle should be possible with existing instruments, through spectroscopic monitoring of an S star concentrated during the months around pericenter, supplemented with an already-adequate astrometric determination of the inclination. In essence, the spectrum of an S star can be considered a heterogeneous ensemble of clocks in a freely falling frame, which near pericenter is moving at relativistic speeds.
- OSTI ID:
- 21562607
- Journal Information:
- Astrophysical Journal Letters, Vol. 734, Issue 1; Other Information: DOI: 10.1088/2041-8205/734/1/L19; ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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