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

Abstract

We have measured the equivalent width (EW) of the K I 7699 A line in a sample of G and K-type members of the ~35 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-V)o < 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 significant scatter. Cluster stars at all colors show potassium EW excesses with respect to field inactive stars; furthermore, a statistically significant relationship is found between differential potassium EWs and log Lx/Lbol ratios, indicating that the EWs of the potassium feature are altered by activity. Our results suggest that the dispersion in Li EWs observed among cluster stars later than (B-V)o ~ 1 cannot be fully explained by the effects of activity. No final conclusion can instead be drawn for earlier-type stars.

accepted by A&A

References in corpus (2)

• Membership, lithium, and metallicity in the young open clusters IC 2602 and IC 2391: enlarging the sample
• The effect of stellar activity on the LiI 6708, NaI 5896 and KI 7699 Ålines: A comparison with the Pleiades, field stars and the Sun

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