We study the structure of relativistic stars in \mathcal { R } + \alpha \mathcal { R } ^ { 2 } 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 \alpha , for uniform density stars matching to the Schwarzschild solution outside the star .
We obtain the mass-radius relations and study the dependence of maximum mass on \alpha .
We find that M _ { \max } \propto \alpha ^ { -3 / 2 } for values of \alpha larger than 10 ~ { } { km ^ { 2 } } .
For each \alpha the maximum mass configuration has the biggest compactness parameter ( \eta = GM / Rc ^ { 2 } ) and we argue that the general relativistic stellar configuration corresponding to \alpha = 0 is the most compact among these .