Relativistic stars in Starobinsky gravity with the matched asymptotic expansions method

We study the structure of relativistic stars in R+αR2 theory using the method of matched asymptotic expansion to handle the higher order derivatives in field equations arising from the higher order curvature term. We find solutions, parametrized by α, for uniform density stars. We obtain the mass-radius relations and study the dependence of maximum mass on α. We find that Mmax is almost linearly proportional to α. For each α the maximum mass configuration has the biggest compactness parameter (η=GM/Rc2), and we argue that the general relativistic stellar configuration corresponding to α=0 is the least compact among these.