We present a grid of models of accreting brown dwarf systems with
circumstellar discs. The calculations involve a self-consistent solution of
both vertical hydrostatic and radiative equilibrium along with a sophisticated
treatment of dust sublimation. We have simulated observations of the spectral
energy distributions and several broadband photometric systems. Analysis of the
disc structures and simulated observations reveal a natural dichotomy in
accretion rates, with \logmdot >−9 and ≤−9 classed as extreme and
typical accretors respectively. Derivation of ages and masses from our
simulated photometry using isochrones is demonstrated to be unreliable even for
typical accretors. Although current brown dwarf disc candidate selection
criteria have been shown to be largely reliable when applied to our model grid
we suggest improved selection criteria in several colour indices. We show that
as accretion rates increase brown dwarf disc systems are less likely to be
correctly identified. This suggests that, within our grid, systems with higher
accretion rates would be preferentially lost during brown dwarf target
selection. We suggest that observations used to assert a M˙∝M∗2
relationship may contain an intrinsic selection bias.Comment: 13 figures, 2 tables, 2 appendices and 25 pages. Accepted for
publication in MNRA