IC 2602: a lithium depletion boundary age and new candidate low-mass stellar members

We report the results from a photometric and spectroscopic survey of similar to 1.4 deg2 of the young open cluster IC 2602. Fourteen objects have been identified as having magnitudes, spectral types and radial velocities consistent with being probable or possible low-mass stellar members of the cluster. We have used the observed location of the lithium depletion boundary in the sequence defined by these objects to place a new and improved constraint on the cluster age, tau = 46+6(-5) Myr. This new determination is larger by a factor similar to 1.3-1.8 than the majority of age estimates which have been obtained using the main-sequence turn-off or pre-main-sequence isochrone techniques. It is thus consistent with the trend indicated by the results of similar studies on other young open clusters. Based on this new age, we set a lower limit on the cluster mass function over the range M = 0.054 - 0.24 M-circle dot, dn/dM > 46 M-1(circle dot). If the mass function of IC 2602 has a form similar to that of other young clusters and associations then future wide, deep surveys can expect to unearth at least a handful of brown dwarfs which could potentially serve as benchmark objects.