Compact Stars in Vector-Tensor-Horndeski Theory of Gravity
  In this paper, we will analyse a theory of modified gravity, in which the field content of general relativity will be increased to include a vector field. We will use the Horndeski formalism to non-minimally couple this vector field to the metric. As we will be using the Horndeski formalism, this theory will not contain Ostrogradsky ghost degree of freedom. We will analyse compact stars using this Vector-Tensor-Horndeski theory. 
Davood Momeni, Mir Faizal, Kairat Myrzakulov, Ratbay Myrzakulov
physics.gen-ph