We have obtained intermediate resolution spectra of 11 candidate brown dwarf members of
the Pleiades open cluster using the Keck II telescope and Low-Resolution Imaging
Spectrograph. Our primary goal was to determine the location of the" lithium depletion edge"
in the Pleiades and hence to derive a precise age for the cluster. All but one of our 11
program objects have radial velocities appropriate for Pleiades members, have moderately
strong H α emission, and have spectral types M6–M8. 5 as expected from their (RI) …

We have identified 27 candidate very low mass members of the relatively young α Persei
open cluster from a 6 deg 2 CCD imaging survey. Based on their I magnitudes and the
nominal age and distance to the cluster, these objects should have masses less than 0.1
Script M☉ if they are cluster members. We subsequently obtained intermediate-resolution
spectra of 17 of these objects using the Keck II telescope and Low-Resolution Imaging
Spectrograph (LRIS). We also obtained near-IR photometry for many of the stars. Our …