Neutral-ion anomaly in cool stars.

An analysis of the abundances in a group of cool stars confirms the presence of the neutral-ion anomaly found by Oinas (1974); i.e., the observed strengths of the ion lines are too strong when compared with the theoretical values calculated from model atmospheres. The effect sets in at a somewhat later spectral type, however, than was found in the earlier paper. The results are shown to be consistent with the work of other investigators. No satisfactory explanation has been found for the anomaly.