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Aims: Our objective is the optical and near-infrared spectroscopic characterisation of 2MASS J0249-0557 c, a recently discovered young planetary mass companion to the $beta$ Pictoris member 2MASS J0249-0557. Methods: Using the Visible and Infrared Survey Telescope for Astronomy (VISTA) Hemisphere Survey (VHS) and the Two Micron All Sky Survey (2MASS) data, we independently identified the companion 2MASS J0249-0557 c. We obtained low-resolution optical spectroscopy of this object using the Optical System for Imaging and low-intermediate-Resolution Integrated Spectroscopy (OSIRIS) spectrograph at the Gran Telescopio Canarias (GTC), and near-infrared spectroscopy using the Son of Isaac (SofI) spectrograph on the New Technology Telescope (NTT). Results: We classified 2MASS J0249-0557 c with a spectral type of L2.5$pm$0.5 in the optical and L3$pm$1 in the near-infrared. We identified spectroscopic indicators of youth that are compatible with the age of the $beta$ Pictoris moving group. We also detect a strong H$alpha$ emission, with a pEW of -90$^{+20}_{-40}$A, which seems persistent in time. This indicates strong chromospheric activity or disk accretion. Although many M-type brown dwarfs have strong H$alpha$ emission, this target is one of the very few L-type planetary mass objects in which this strong H$alpha$ emission has been detected. Lithium absorption at 6708 A is observed with pEW $lesssim$ 5A. We also computed the binding energy of 2MASS J0249-0557 c and obtained an (absolute) upper limit of $U=(-8.8pm4.4) 10^{32}$ J. Conclusions: Similarly to other young brown dwarfs and isolated planetary mass objects, strong H$alpha$ emission is also present in young planetary mass companions at ages of some dozen million years. We also found that 2MASS J0249-0557 c is one of the wide substellar companions with the lowest binding energy known to date.
We have discovered a wide planetary-mass companion to the $beta$ Pic moving group member 2MASSJ02495639-0557352 (M6 VL-G) using CFHT/WIRCam astrometry from the Hawaii Infrared Parallax Program. In addition, Keck laser guide star adaptive optics apert
We present the identification of two previously known young objects in the solar neighbourhood as a likely very wide binary. TYC 9486-927-1, an active, rapidly rotating early-M dwarf, and 2MASS J21265040-8140293, a low-gravity L3 dwarf previously ide
We present a photometric $J$-band variability study of GU Psc b, a T3.5 co-moving planetary-mass companion (9-13$M_{rm{Jup}}$) to a young ($sim$150 Myr) M3 member of the AB Doradus Moving Group. The large separation between GU Psc b and its host star
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)
The Young Suns Exoplanet Survey (YSES) consists of a homogeneous sample of 70 young, solar-mass stars located in the Lower Centaurus-Crux subgroup of the Scorpius-Centaurus association with an average age of $15pm3,$Myr. We report the detection of a