A review on substellar objects beyond the deuterium burning mass limit:\n planets, brown dwarfs or what?

"Free-floating, non-deuterium-burning, substellar objects" are isolated\nbodies of a few Jupiter masses found in very young open clusters and\nassociations, nearby young moving groups and in the immediate vicinity of the\nSun. They are neither brown dwarfs nor planets. I look over their nomenclature,\nhistory of discovery, sites of detection, formation mechanisms and future\ndirections of research. Most free-floating, non-deuterium-burning, substellar\nobjects share the same formation mechanism as low-mass stars and brown dwarfs,\nbut there are still a few caveats, such as the value of the opacity mass limit,\nthe minimum mass at which an isolated body can form via turbulent fragmentation\nfrom a cloud. The least massive free-floating substellar objects found to date\nhave masses of about 0.004 Msol, but current and future surveys should aim at\nbreaking this record. For that, we may need LSST, Euclid and WFIRST.\n