Minimum magnetic-equilibrium spin period
= Minimum magnetic-equilibrium spin period
{title2=$T_{\min}\propto B_*^{6/7}R_*^{15/7}$}
With <magnetic spin equilibrium> at the <magnetospheric truncation radius>, $T\propto R_M^{3/2}M^{-1/2}\propto B_*^{6/7}R_*^{18/7}\dot M^{-3/7}$ at fixed <mass>. Inserting the <surface accretion Eddington rate> changes the radius power to $15/7$. The relation assumes the boundary remains outside the star; very weak fields instead encounter surface-accretion and <mass-shedding limits>.