We present the discovery of a companion near the deuterium burning mass limit located at a very wide distance , at an angular separation of 4.6 \pm 0.1″ ( projected distance of \sim 670 AU ) from UScoCTIO 108 , a brown dwarf of the very young Upper Scorpius association .
Optical and near-infrared photometry and spectroscopy confirm the cool nature of both objects , with spectral types of M7 and M9.5 , respectively , and that they are bona fide members of the association , showing low gravity and features of youth .
Their masses , estimated from the comparison of their bolometric luminosities and theoretical models for the age range of the association , are 60 \pm 20 and 14 ^ { +2 } _ { -8 } M _ { Jup } , respectively .
The existence of this object around a brown dwarf at this wide orbit suggests that the companion is unlikely to have formed in a disk based on current planet formation models .
Because this system is rather weakly bound , they did not probably form through dynamical ejection of stellar embryos .