Planetary-mass binaries in Lower Centaurus-Crux

We find 17 young low-mass binaries in the LCC association, with distances starting from 68pc and projected separations ranging from 88au to 6742au. A couple of candidates have additional faint companions that need confirmation to secure them as triple systems. Adopting an age of 17Myr for the LCC association, we find that 14 of the components are faint enough to have planetary masses.

Our results indicate that binaries represent >~2% of the population of FFPs in the LCC association, and suggest that their preferred formation mechanism is the gravitational collapse independent of a star. Also, many of the recently discovered FFPs in LCC may be unresolved giant binary planets. The wide range of colors and flux reversals observed suggests that the existence of clouds in their atmospheres is important and points to continuity with the BD populations.