Dusko Borka
Orbits of S2 star in Yukawa gravity: simulations vs observations
We investigate some possible observational signatures of Yukawa gravity at Galactic scales. We performed simulations in Yukawa gravity potential and analyzed the obtained trajectories of S2 star around Galactic center. We compare the obtained theoretical results for S2 star orbit in the Yukawa potential with two independent sets of observations of the S2 star obtained by New Technology Telescope/Very Large Telescope (NTT/VLT), as well as by Keck telescope. Our results show that the most probable value for the parameter \Lambda in Yukawa gravity potential in the case of S2 star is around 5000 - 7000 AU. At the same time, we were not able to obtain reliable constrains on the universal constant \delta of Yukawa gravity, because the current observations of S2 star indicated that it may be highly correlated with parameter \Lambda. We obtained that the Yukawa gravity potential induces precession of S2 star orbit in the same direction as General Relativity for \delta > 0 and for \delta < -1, and in the opposite direction for -1 <\delta < 0.