  We point out that the CP asymmetries in the decays $D^0\rightarrow K_{S}
K^{*0}$ and $D^0\rightarrow K_{S} \overline{K}{}^{*0}$ are potential discovery
channels for charm CP violation in the Standard Model. We stress that no flavor
tagging is necessary, the untagged CP asymmetry $a_{CP}^{\mathrm{dir}}(D \to
K_S K^{*0})$ is essentially equal to the tagged one, so that the untagged
measurement comes with a significant statistical gain. Depending on the
relevant strong phase, $\vert a_{CP}^{\text{dir, untag}}\vert$ can be as large
as $0.003$. The CP asymmetry is dominantly generated by exchange diagrams and
does not require non-vanishing penguin amplitudes. While the CP asymmetry is
smaller than in the case of $D^0\rightarrow K_SK_S$, the experimental analysis
is more efficient due to the prompt decay $K^{*0}\rightarrow K^+\pi^-$. One may
further search for favourable strong phases in the Dalitz plot in the vicinity
of the $K^{*0}$ peak.

High Energy Physics - Phenomenology