Constraining Scalar-Tensor gravity models by S2 star orbits around the
  Galactic Center
  The aim of our investigation is to derive a particular theory among the class
of scalar-tensor(ST) theories of gravity, and then to test it by studying
kinematics and dynamics of S-stars around supermassive black hole (BH) at
Galactic Center (GC). We also discuss the Newtonian limit of this class of ST
theories of gravity, as well as its parameters. We compare the observed orbit
of S2 star with our simulated orbit which we obtained theoretically with the
derived ST potential and constrained the parameters. Using the obtained best
fit parameters we calculated orbital precession of S2 star in ST gravity,and
found that it has the same direction as in General Relativity (GR), but causes
much larger pericenter shift.
