For an abelian variety $A$ with formal group $F$, how is the formal group $F^\ast$ of the dual abelian variety $A^{\vee}$ related to $F$? In general, for a formal group $F$, is there a concept of dual formal group $F^\ast$? If so, how is it defined? I think this is related to the cartier dual, but could you give a simple description of $F^*$?
Any reference or insight would be very helpful.