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We discover that the very low-mass brown dwarf OTS44 (M9.5, ~12 M_Jup) hassignificant accretion and a substantial disk, which demonstrates that theprocesses that accompany canonical star formation occur down to a central massof a few Jupiter masses. We discover in VLT/SINFONI spectra that OTS44 hasstrong, broad, and variable Paschen beta emission that is evidence for activeaccretion at the planetary border. We also detect strong Halpha emission ofOTS44 in a literature spectrum and determine an Halpha EW (-141 A) that isindicative of active accretion. Both the Pa beta and Halpha emission lines havebroad profiles with wings extending to velocities of about +/-200 km/s. Wedetermine 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 rateconsidering its small central mass. This mass rate is nevertheless consistentwith the general decreasing trend found for stars of several solar masses downto brown dwarfs. Furthermore, we determine the properties of the disksurrounding OTS44 through radiative transfer modeling of flux measurement fromthe optical to the far-IR (Herschel) by applying a Bayesian analysis. We findthat 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 ofdisk-to-central-mass of about 10^{-2} found for objects between 0.03 Msun and14 Msun is also valid for OTS44 at a mass of ~0.01 M_Sun. Our observations arein line with an isolated star-like mode of the formation of brown dwarfs downto 0.01 M_Sun.

OTS44: Disk and accretion at the planetary border