The proximity of the Galactic Center allows for the study of the influence of a central black hole on its immediate vicinity in much greater detail than in other galactic nuclei. The supermassive black hole SgrA* in the Galactic Center is enshrouded in a cluster of young stars on deeply plunging orbits, which serve as luminous test masses to probe its strong gravitational potential and even test General Relativity.
The near-infrared beam combiner instrument GRAVITY at ESO’s VLTI has determined the mass of SgrA* to an unprecedented precision and detected the relativistic Schwarzschild precession in the orbit of a comparably bright star. Besides its mass, a black hole is further characterized, according to the no-hair theorem, by its angular momentum and electric charge. Following the precise measurement of the mass of SgrA*, the next step would be to constrain its spin.
We present the discovery of a highly eccentric faint star in the Galactic Center, named S301, that is sensitive to the spin of SgrA*. It was first detected in GRAVITY images of the Galactic Center in 2023 and has since been followed up on with dedicated observing campaigns. The orbit of S301 is unique ; its orbital period is just 8.7 years, and it is approaching SgrA* during its pericenter passage to a mere 140 Schwarzschild radii.
We provide a detailed explanation of the image reconstruction method for GRAVITY which was employed to detect S301. We discuss the orbit of S301, its possible implications for star formation in the Galactic Center, and prospects for a potential spin detection of SgrA* with upcoming facilities.
Discovery of a highly eccentric, faint star in the Galactic Center sensitive to the spin of the black hole SgrA*
Lundi 24 novembre 2025
de
11:00 à
12:00
salle 204 du bâtiment Schatzman (18)
