Poster Abstracts

Name/Affiliation:  Philippe Gondoin (European Space Agency)

Title:  Lithium abundance and rotation in the Pleiades and M34 open clusters

K-type stars of similar effective temperatures in clusters younger than about 250 Myrs are characterised by a wide dispersion in lithium abundance whose origin is not understood. Photometric monitoring programs indicate that young stars tend to group into two main populations that lie on narrow sequences in diagrams where the measured rotation periods of the members of a stellar cluster are plotted against their (B - V) colours. I report on the results of a study that investigated the dependence of lithium abundance with effective temperature distinguishing stars that belong to different rotation sequences in the Pleiades and M34 open clusters.