A NEAR-INFRARED SEARCH FOR BROWN DWARFS IN THE PLEIADES

Deep mosaic imaging of 200 arcmin2 of the Pleiades was conducted at wavelengths of 0.9-mu-m (I band) and 2.2-mu-m (K band) in an effort to find free-floating low-mass cluster members. Control fields outside of the cluster, totalling 75 arcmin2, were also imaged to check the overall significance of the results. Photometry of all detected point sources led to the detection of 22 +/- 10 objects, when compared to the control data set, that lie near the lower Pleiades main sequence. These objects have theoretical masses in the range of approximately 0.1-0.04 M . and are described by a power-law mass distribution (dN/dm is-proportional-to m(alpha)) with a slope of -2.8 +/- 0.5. If the detected objects are true cluster members, their combined mass would contribute significantly to that of the Pleiades.