Hořava gravity breaks boost invariance in the gravitational sector by introducing a preferred time foliation .
The dynamics of this preferred slicing is governed , in the low-energy limit suitable for most astrophysical applications , by three dimensionless parameters \alpha , \beta and \lambda .
The first two of these parameters are tightly bound by solar system and gravitational wave propagation experiments , but \lambda remains relatively unconstrained ( 0 \leq \lambda \lesssim 0.01 - 0.1 ) .
We restrict here to the parameter space region defined by \alpha = \beta = 0 ( with \lambda kept generic ) , which in a previous paper we showed to be the only one where black hole solutions are non-pathological at the universal horizon , and we focus on possible violations of the strong equivalence principle in systems involving neutron stars .
We compute neutron star “ sensitivities ” , which parametrize violations of the strong equivalence principle at the leading post-Newtonian order , and find that they vanish identically , like in the black hole case , for \alpha = \beta = 0 and generic \lambda \neq 0 .
This implies that no violations of the strong equivalence principle ( neither in the conservative sector nor in gravitational wave fluxes ) can occur at the leading post-Newtonian order in binaries of compact objects , and that data from binary pulsars and gravitational interferometers are unlikely to further constrain \lambda .