Deuterium burning in substellar objects

We consider the depletion of primordial deuterium in the interior of subste llar objects as a function of mass, age, and absolute magnitude in several photometric passbands. We characterize potential spectroscopic signatures o f deuterium in the lines of deuterated water HDO. These results will serve as a useful, independent diagnostic to characterize the mass and/or the age of young substellar objects and to provide an independent age determinatio n of very young clusters. These results can serve to identify objects at th e deuterium-burning limit and to confront the theoretical prediction that D burning is a necessary condition to form starlike objects.