  We discover that the very low-mass brown dwarf OTS44 (M9.5, ~12 M_Jup) has
significant accretion and a substantial disk, which demonstrates that the
processes that accompany canonical star formation occur down to a central mass
of a few Jupiter masses. We discover in VLT/SINFONI spectra that OTS44 has
strong, broad, and variable Paschen beta emission that is evidence for active
accretion at the planetary border. We also detect strong Halpha emission of
OTS44 in a literature spectrum and determine an Halpha EW (-141 A) that is
indicative of active accretion. Both the Pa beta and Halpha emission lines have
broad profiles with wings extending to velocities of about +/-200 km/s. We
determine the mass accretion rate of OTS44 based on Halpha to 7.6x10^{-12}
Msun/yr, which shows that OTS44 has a relatively high mass-accretion rate
considering its small central mass. This mass rate is nevertheless consistent
with the general decreasing trend found for stars of several solar masses down
to brown dwarfs. Furthermore, we determine the properties of the disk
surrounding OTS44 through radiative transfer modeling of flux measurement from
the optical to the far-IR (Herschel) by applying a Bayesian analysis. We find
that OTS44 has a highly flared disk (beta >1.2) with a mass of 9.1x10^{-5}
M_Sun, i.e. about 0.1 M_Jup or 30 M_Earth. We show that the ratio of
disk-to-central-mass of about 10^{-2} found for objects between 0.03 Msun and
14 Msun is also valid for OTS44 at a mass of ~0.01 M_Sun. Our observations are
in line with an isolated star-like mode of the formation of brown dwarfs down
to 0.01 M_Sun.

Solar and Stellar Astrophysics