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We present the discovery of a co-moving planetary-mass companion ∼ 42 ′′ (∼ 2000 AU) from a young M3 star, GU Psc, likely member of the young AB Doradus Moving Group (ABDMG). The companion was first identified via its distinctively red i-z color (> 3.5) through a survey made with Gemini-S/GMOS. Follow-up Canada-France-Hawaii Telescope/WIRCam near-infrared (NIR) imaging, Gemini-N/GNIRS NIR spectroscopy and Wide-field Infrared Survey Explorer photometry indicate a spectral type of T3.5 ± 1 and reveal signs of low gravity which we attribute to youth. Keck/Adaptive Optics NIR observations did not resolve the companion as a binary. A comparison with atmosphere models indicates T eff = 1000-1100 K and log g = 4.5-5.0. Based on evolution models, this temperature corresponds to a mass of 9-13 M Jup for the age of ABDMG (70-130 Myr). The relatively well-constrained age of this companion and its very large angular separation to its host star will allow its thorough characterization and will make it a valuable comparison for planetary-mass companions that will be uncovered by forthcoming planet-finder instruments such as Gemini Planet Imager and SPHERE.

Context. 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. 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. 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. Results. We report here the direct-imaging discovery of 2MASS J01033563-5515561(AB)b, a 12-14 M Jup companion at a projected separation of 84 AU from a pair of young late-M stars, with which it shares proper motion. We also detected a Keplerian-compatible orbital motion. Conclusions. This young L-type object at the planet/brown dwarf mass boundary is the first ever imaged around a binary system at a separation compatible with formation in a disc.

We present the first statistical analysis of exoplanet direct imaging surveys combining adaptive optics (AO) imaging at small separations with deep seeing-limited observations at large separations allowing us to study the entire orbital separation domain from 5 to 5000 au simultaneously. Our sample of 344 stars includes only confirmed members of nearby young associations and is based on all AO direct-imaging detection limits readily available online, with addition of our own previous seeing-limited surveys. Assuming that the companion distribution in mass and a semimajor axis follows a power-law distribution and adding a dependence on the mass of the host star, such as , we constrain the parameters to obtain , , and at a 68% confidence level, and we obtain for the overall planet occurrence rate for companions with masses between 1 and 20 in the range of 5–5000 au. Thus, we find that occurrence of companions is negatively correlated with a semimajor axis and companion mass (marginally) but is positively correlated with the stellar host mass. Our inferred mass distribution is in good agreement with other distributions found previously from direct imaging surveys for planets and brown dwarfs, but is shallower as a function of mass than the distributions inferred by radial velocity surveys of gas giants in the 1–3 au range. This may suggest that planets at these wide and very wide separations represent the low-mass tail of the brown dwarfs and stellar companion distribution rather than an extension of the distribution of the inner planets.

We present the results of a direct-imaging survey for very large separation (>100 au), companions around 95 nearby young K5-L5 stars and brown dwarfs. They are high-likelihood candidates or confirmed members of the young ( < ∼ 150 Myr) β Pictoris and AB Doradus moving groups (ABDMG) and the TW Hya, Tucana-Horologium, Columba, Carina, and Argus associations. Images in i and z filters were obtained with the Gemini Multi-Object Spectrograph (GMOS) on Gemini South to search for companions down to an apparent magnitude of z ∼ 22-24 at separations > ∼ 20 from the targets and in the remainder of the wide 5. 5 × 5. 5 GMOS field of view. This allowed us to probe the most distant region where planetary-mass companions could be gravitationally bound to the targets. This region was left largely unstudied by past high-contrast imaging surveys, which probed much closer-in separations. This survey led to the discovery of a planetary-mass (9-13 M Jup ) companion at 2000 au from the M3V star GU Psc, a highly probable member of ABDMG. No other substellar companions were identified. These results allowed us to constrain the frequency of distant planetarymass companions (5-13 M Jup ) to 0.84 +6.73 −0.66 % (95% confidence) at semimajor axes between 500 and 5000 au around young K5-L5 stars and brown dwarfs. This is consistent with other studies suggesting that gravitationally bound planetary-mass companions at wide separations from low-mass stars are relatively rare.

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We report the discovery of a substellar companion to 2MASS J02192210-3925225, a young M6 γ candidate member of the Tucana-Horologium association (30 − 40 Myr). This L4 γ companion has been discovered with seeing-limited direct imaging observations; at a 4 ′′ separation (160 AU) and a modest contrast ratio, it joins the very short list of young low-mass companions amenable to study without the aid of adaptive optics, enabling its characterization with a much wider suite of instruments than is possible for companions uncovered by high-contrast imaging surveys. With a model-dependent mass of 12-15 M Jup , it straddles the boundary between the planet and brown dwarf mass regimes. We present near-infrared spectroscopy of this companion and compare it to various similar objects uncovered in the last few years. The J0219-3925 system falls in a sparsely populated part of the host mass versus mass ratio diagram for binaries; the dearth of known similar companions may be due to observational biases in previous low-mass companion searches.

We report results from the Wide-orbit Exoplanet search with InfraRed Direct imaging, or WEIRD, a survey designed to search for Jupiter-like companions on very wide orbits (1000-5000 au) around young stars (<120 Myr) that are known members of moving groups in the solar neighborhood (<70 pc). Companions that share the same age, distance, and metallicity as their host while being on large enough orbits to be studied as "isolated" objects make prime targets for spectroscopic observations, and they are valuable benchmark objects for exoplanet atmosphere models. The search strategy is based on deep imaging in multiple bands across the near-infrared domain. For all 177 objects of our sample, ¢ z ab , J, [3.6], and [4.5] images were obtained with CFHT/MegaCam, GEMINI/GMOS, CFHT/WIRCam, GEMINI/Flamingos-2, and Spitzer/IRAC. Using this set of four images per target, we searched for sources with red ¢ z ab and [3.6]-[4.5] colors, typically reaching good completeness down to 2 M Jup companions, while going down to 1 M Jup for some targets, at separations of 1000-5000 au. The search yielded four candidate companions with the expected colors, but they were all rejected through follow-up proper motion observations. Our results constrain the occurrence of 1-13 M Jup planetary-mass companions on orbits with a semimajor axis between 1000 and 5000 au at less than 0.03, with a 95% confidence level.