CFBDSIR 2149-0403: young isolated planetary-mass object or high-metallicity low-mass brown dwarf?

We conducted a multi-wavelength, multi-instrument observational characterisation of the candidate free-floating planet CFBDSIR~J214947.2-040308.9, a late T-dwarf with possible low-gravity features, in order to constrain its physical properties. We analyzed 9 hours of X-Shooter spectroscopy with sign...

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Bibliographic Details
Main Authors: Delorme, Philippe (Author) , Homeier, Derek (Author)
Format: Article (Journal) Chapter/Article
Language:English
Published: March 3, 2017
In: Arxiv

Online Access:Verlag, kostenfrei, Volltext: http://arxiv.org/abs/1703.00843
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Author Notes:P. Delorme, T. Dupuy, J. Gagné, C. Reylé, T. Forveille, Michael C. Liu, E. Artigau, L. Albert, X. Delfosse, F. Allard, D. Homeier, L. Malo, C. Morley, M.E. Naud and M. Bonnefoy
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Summary:We conducted a multi-wavelength, multi-instrument observational characterisation of the candidate free-floating planet CFBDSIR~J214947.2-040308.9, a late T-dwarf with possible low-gravity features, in order to constrain its physical properties. We analyzed 9 hours of X-Shooter spectroscopy with signal detectable from 0.8--2.3$\mu$m, as well as additional photometry in the mid-infrared using the Spitzer Space Telescope. Combined with a VLT/HAWK-I astrometric parallax, this enabled a full characterisation of the absolute flux from the visible to 5$\mu$m, encompassing more than 90\% of the expected energy emitted by such a cool late T-type object. Our analysis of the spectrum also provided the radial velocity and therefore the determination of its full 3-D kinematics. While our new spectrum confirms the low gravity and/or high metallicity of CFBDSIR2149, the parallax and kinematics safely rule out membership to any known young moving group, including AB~Doradus. We use the equivalent width of the KI doublet at 1.25$\m
Item Description:Gesehen am 11.10.2017
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