On the dispersion in lithium and potassium among late-type stars in young clusters: IC 2602

We have measured the equivalent width (EW )o f the Ki 7699 A line in a sample of G and K{type members of the35 Myr old cluster IC 2602 for which a dispersion in Li EWs had been reported by previous studies. Active cluster stars with 0:75 <B V0 < 1 are characterized by a dispersion in the EW of the K i 7699 A, while earlier and later{type stars do not show any signicant scatter. Cluster stars at all colors show potassium EW excesses with respect to eld inactive stars; furthermore, a statistically signicant relationship is found between dierential potassium EW sa nd logLX=Lbol ratios, indicating that the EWs of the potassium feature are altered by activity. Our results suggest that the dispersion in LiEWs observed among cluster stars later than B V0 1 cannot be fully explained by the eects of activity. No nal conclusion can instead be drawn for earlier{type stars.