Constraining the range of Yukawa gravity interaction from S2 star orbits

Abstract

We consider possible signatures for Yukawa gravity within the Galactic Central Parsec, based on our analysis of the S2 star orbital precession around the massive compact dark object at the Galactic Centre, and on the comparisons between the simulated orbits in Yukawa gravity and two independent sets of observations. Our simulations resulted in strong constraints on the range of Yukawa interaction Lambda and showed that its most probable value 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 in the range (0 LT delta LT 1). For delta GT 2 they are not correlated. However, the same universal constant which was successfully applied to clusters of galaxies and rotation curves of spiral galaxies (delta = 1/3) also gives a satisfactory agreement with the observed orbital precession of the S2 star, and in that case the most probable value for the scale parameter is Lambda approximate to 3000 +/- 1500 AU. Also, the Yukawa gravity potential induces precession of S2 star orbit in the same direction as General Relativity for delta GT 0 and for delta LT -1, and in the opposite direction for -1 LT delta LT 0. The future observations with advanced facilities, such as GRAVITY or/and European Extremely Large Telescope, are needed in order to verify these claims.