Talk abstract

It appears that a brown dwarf in a wide orbit (> 100 AU) around a Sun-like star is more likely than a field brown dwarf to be in a close (~ 5 AU) binary system with another brown dwarf. In principle these close BD/BD binaries could have formed elsewhere, and then been captured. By means of a large ensemble of N-body simulations, we show that this has too low probability to play a significant role in their genesis. This them implies that close BD/BD binaries are formed in orbit around Sun-like stars, possibly by disc fragmentation.