  Almost by definition brown dwarfs are objects with masses below the hydrogen
burning limit, around $0.07\ M_\odot$. Below this mass, objects never reach a
steady state where they can fuse hydrogen. Here we demonstrate, in contrast to
this traditional view, that brown dwarfs with masses greater than the hydrogen
burning limit may in principle exist in the universe. These objects, which we
term "overmassive brown dwarfs" form a continuous sequence with traditional
brown dwarfs in any property (mass, effective temperature, radius, luminosity).
To form an overmassive brown dwarf, mass must be added sufficiently slowly to a
sufficiently old traditional brown dwarf below the hydrogen burning limit. We
identify mass transfer in binary brown dwarf systems via Roche lobe overflow
driven by gravitational waves to be the most plausible mechanism to produce the
bulk of the putative overmassive brown dwarf population.
