  We consider a modified action functional with a non-minimum coupling between
the scalar curvature and the matter Lagrangian, and study its consequences on
stellar equilibrium. Particular attention is paid to the validity of the
Newtonian regime, and on the boundary and exterior matching conditions, as well
as on the redefinition of the metric components. Comparison with solar
observables is achieved through numerical analysis, and constraints on the
non-minimum coupling are discussed.
