Nuclear and nonnuclear abundance patterns in the manganese stars

The manganese stars show abundance anomalies that are in conflict with the predictions of nuclear astrophysics. We stress the deviations from the odd-even effect that occur for phosphorus, gallium, and yttrium. The abundance anomalies (e.g., the Mn/Fe ratio) in the iron peak are less serious; within the uncertainties of the current determinations, they may be explained in terms of the same processes that predict the solar-system abundances