other groups investigated within 75 pc (Ursa Majoris, Carina Near, Tucana Horologium, Hyades, Argus, TWA), all yielded probabilities of $<$10$^{-17}$%. If one sums the individual marginal group and field star membership probabilities and assigns equal weights, then we estimate that 2M0355 has a 42% chance of being an AB Doradus member, a 58% chance of being a field star, and a $<$0.04% chance of being a $\beta$ Pictoris group member. Further work calculating the relative densities of the young stellar groups could refine these probabilities, but at this point it appears most plausible that 2M0355 is either a member of the AB Doradus moving group or a field star. Given the photometric and spectroscopic evidence for youth shown here-in combined with the low density of very young field stars, we believe that the kinematic evidence points towards 2M0355 being a likely member of the AB Doradus group.

Discussion
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Among the known population of low surface gravity L dwarfs, 2M0355+11 is the latest spectral type or one of the coolest isolated young brown dwarfs known. To extend the comparison of young brown dwarfs and planetary-mass objects, we investigate the colors and luminosities of 2M1207b and the directly imaged planets HR 