2009A&A...508..859B

We search for brown dwarfs at the Class 0/I evolutionary stage, or proto brown dwarfs. We present a multi wavelength study, ranging from optical at 0.8µm to radio wavelengths at 6cm, of a cool, very faint, and red multiple object, SSTB213 J041757, detected by Spitzer toward the Barnard 213 dark cloud, in Taurus. The SED of SSTB213 J041757 displays a clear excess at long wavelengths resembling that of a Class I object. The mid-IR source has two possible counterparts, A and B, in the near-IR and optical images, and the 350 µm observations detect clear extended emission, presumably from an envelope around the two sources. The position of A & B in the (Ic-J) versus (J-[3.6]) colour-colour diagram is consistent with them being Galactic sources and not extragalactic contaminants. A proper-motion study confirms this result for A, while it is inconclusive for B. The temperature and mass of the two possible central objects, according to COND evolutionary models, range between 1550-1750K and 3-4M_Jupiter, and 950-1300K and 1-2M_Jupiter, for A and B, respectively. The integrated SED provides bolometric temperatures and luminosities of 280K and 0.0034L_☉, assuming that the emission at wavelengths >5µm is associated with component A, and 150K and 0.0033L_☉, assuming that the emission at wavelengths >5µm is associated with component B, which would imply the SSTB213 J041757 object has a luminosity well below the luminosity of other very low luminosity objects discovered up to date. With these characteristics, SSTB213 J041757 seems to be a promising, and perhaps double, proto brown dwarf candidate.