We also detected a Keplerian-compatible orbital motion. Results: We report here the direct-imaging discovery of 2MASS J01033563-5515561(AB)b, a 12-14 MJup companion at a projected separation of 84 AU from a pair of young late-M stars, with which it shares proper motion. Methods: We have been conducting an adaptive optic imaging survey to search for planetary-mass companions of young M dwarfs in the solar neigbourhood, in order to probe different initial conditions of planetary formation. Aims: Since many of these newly imaged giant planets orbit massive A or even B stars, we investigate whether giant planets could be found orbiting low-mass stars at large separations. Though only a handful of extrasolar planets have been discovered via direct-imaging, each of these discoveries had a tremendous impact on our understanding of planetary formation, stellar formation, and cool atmosphere physics. This BD formation mechanism appears to avoid some of the problems associated with the `embryo ejection' scenario, and to answer some of the questions not yet answered by the `turbulent fragmentation' scenario. Some BDs form close BD/BD binaries, and these binaries can survive ejection into the field. The majority are released into the field by interactions amongst themselves in so doing they acquire only a low velocity dispersion (<~2kms-1), and therefore they usually retain small discs, capable of registering an infrared excess and sustaining accretion. A few of the BDs formed in this way remain attached to the primary star, orbiting at large radii. We suggest that low-mass hydrogen-burning stars like the Sun should sometimes form with massive extended discs, and we show, by means of radiation hydrodynamic simulations, that the outer parts of such discs (R >~ 100au) are likely to fragment on a dynamical time-scale (103 to 104yr), forming low-mass companions: principally brown dwarfs (BDs), but also very low-mass hydrogen-burning stars and planetary-mass objects. It seems likely therefore that advances in observational techniques, such as infrared astronomy and microlensing, will lead to the discovery of many more free-floating planets in the future, securing their recognition as genuine astrophysical objects. The number of unbound planets however may exceed the number of stars by two orders of magnitude, although most of them should be low-mass rock/ice planetary embryos ejected from planetary systems in formation. Estimates of the abundance of these objects suggest that planetars in the mass range of 1 – 13 M♃ may be about as common as stars and brown dwarfs. Three possible scenarios of planetar formation and four scenarios of unbound planet origin are explored and discussed. We designate the former type of object a planetar and the latter an unbound planet. It is suggested that free floating planets can originate in two settings: 1) interstellar space, where the object forms in the manner of a star 2) circumstellar space, where the object forms in the manner of a conventional planet and is subsequently lost to interstellar space. In this paper, this evidence and the history of the concept of free-floating planets is reviewed and a classification is proposed, based on mode of origin. Evidence for the existence of planetary mass objects, unattached to any star and free-floating in interstellar space, has recently emerged.
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