IC348-SMM2E: a Class 0 proto-brown dwarf candidate forming as a
  scaled-down version of low-mass stars
  We report on Submillimeter Array observations of the 870 micron continuum and
CO(3-2), 13CO(2-1) and C18O(2-1) line emission of a faint object, SMM2E, near
the driving source of the HH797 outflow in the IC348 cluster. The continuum
emission shows an unresolved source for which we estimate a mass of gas and
dust of 30 Mjup, and the CO(3-2) line reveals a compact bipolar outflow centred
on SMM2E, and barely seen also in 13CO(2-1). In addition, C18O(2-1) emission
reveals hints of a possible rotating envelope/disk perpendicular to the
outflow, for which we infer a dynamical mass of ~16 Mjup. In order to further
constrain the accreted mass of the object, we gathered data from Spitzer,
Herschel, and new and archive submillimetre observations, and built the
Spectral Energy Distribution (SED). The SED can be fitted with one single
modified black-body from 70 micron down to 2.1 cm, using a dust temperature of
~24 K, a dust emissivity index of 0.8, and an envelope mass of ~35 Mjup. The
bolometric luminosity is 0.10 Lsun, and the bolometric temperature is 35 K.
Thus, SMM2E is comparable to the known Class 0 objects in the stellar domain.
An estimate of the final mass indicates that SMM2E will most likely remain
substellar, and the SMM2E outflow force matches the trend with luminosity known
for young stellar objects. Thus, SMM2E constitutes an excellent example of a
Class 0 proto-brown dwarf candidate which forms as a scaled-down version of
low-mass stars. Finally, SMM2E seems to be part of a wide (~2400 AU) multiple
system of Class 0 sources.
