  The autoionization of core-excited Rydberg states is theoretically studied
for a broad range of principal and angular-momentum quantum numbers $n$ and
$\ell$ in alkaline-earth-metal atoms. We combined two theoretical methods to
calculate accurate autoionization rates for $n=10-65$ and $\ell=0-45$ over the
100 orders of magnitude that they span. The strong interaction between the two
valence electrons for low $\ell$ states is treated from first principles with
configuration interaction with exterior complex scaling, while at large $\ell$
the weak correlation is described by a perturbative approach and
arbitrary-precision floating-point arithmetics. The results, which we benchmark
against available experimental data, provide autoionization rates for the
$Np_{1/2, 3/2}$ and, when applicable, $(N-1)d_{3/2, 5/2}$ ion-core states of
Mg, Ca and Sr ($N=3-5$). Using the extensive set of calculated data, we analyze
the dependence of the rates on $\ell$ and identify five general laws of the
autoionization of high-$\ell$ states. An empirical formula describing the
scaling of the rates with $\ell$ is suggested.
