Modified gravity inside astrophysical bodies

Understand

Many theories of modified gravity, including the well studied Horndeski models, are characterized by a screening mechanism that ensures that standard gravity is recovered near astrophysical bodies.

• In a recently introduced class of gravitational theories that goes beyond Horndeski, it has been found that new derivative interactions lead to a partial breaking of the Vainshtein screening mechanism inside any gravitational source, although not outside.
• We study the impact of this new type of deviation from standard gravity on the density profile of a spherically symmetric matter distribution, in the nonrelativistic limit.
• For simplicity, we consider a polytropic equation of state and derive the modifications to the standard Lane-Emden equations.