1-2.4 μm Near-IR Spectrum of the Giant Planet β Pictoris b Obtained with the Gemini Planet Imager

Jeffrey Chilcote , Laurent Pueyo , Robert J. de Rosa , Jeffrey Vargas , Bruce Macintosh , Vanessa P. Bailey , Travis Barman , Brian Bauman , Sebastian Bruzzone , Joanna Bulger , Adam S. Burrows , Andrew Cardwell , Christine H. Chen , Tara Cotten , Daren Dillon , Rene Doyon , Zachary H. Draper , Gaspard Duchêne (1) , Jennifer Dunn , Darren Erikson , Michael P. Fitzgerald , Katherine B. Follette , Donald Gavel , Stephen J. Goodsell , James R. Graham , Alexandra Z. Greenbaum , Markus Hartung , Pascale Hibon , Li-Wei Hung , Patrick Ingraham , Paul Kalas , Quinn Konopacky , James E. Larkin , Jérôme Maire , Franck Marchis , Mark S. Marley , Christian Marois , Stanimir Metchev , Maxwell A. Millar-Blanchaer , Katie M. Morzinski , Eric L. Nielsen , Andrew Norton , Rebecca Oppenheimer , David Palmer , Jennifer Patience , Marshall Perrin , Lisa Poyneer , Abhijith Rajan , Julien Rameau , Fredrik T. Rantakyrö , Naru Sadakuni , Leslie Saddlemyer , Dmitry Savransky , Adam C. Schneider , Andrew Serio , Anand Sivaramakrishnan , Inseok Song , Remi Soummer , Sandrine Thomas , J. Kent Wallace , Jason J. Wang , Kimberly Ward-Duong , Sloane Wiktorowicz , Schuyler Wolff

1 IPAG - Institut de Planétologie et d'Astrophysique de Grenoble

Using the Gemini Planet Imager located at Gemini South, we measured the near-infrared (1.0-2.4 μm) spectrum of the planetary companion to the nearby, young star β Pictoris. We compare the spectrum obtained with currently published model grids and with known substellar objects and present the best matching models as well as the best matching observed objects. Comparing the empirical measurement of the bolometric luminosity to evolutionary models, we find a mass of 12.9 ± 0.2 {{ M }}_{Jup}, an effective temperature of 1724 ± 15 K, a radius of 1.46 ± 0.01 {{ R }}_{Jup}, and a surface gravity of {log}g=4.18+/- 0.01 [dex] (cgs). The stated uncertainties are statistical errors only, and do not incorporate any uncertainty on the evolutionary models. Using atmospheric models, we find an effective temperature of 1700-1800 K and a surface gravity of {log}g=3.5-4.0 [dex] depending upon the model. These values agree well with other publications and with “hot-start” predictions from planetary evolution models. Further, we find that the spectrum of β Pic b best matches a low surface gravity L2 ± 1 brown dwarf. Finally, comparing the spectrum to field brown dwarfs, we find the the spectrum best matches 2MASS J04062677-381210 and 2MASS J03552337+1133437.

Mots clés: instrumentation: adaptive optics; planetary systems; stars: individual: beta Pictoris; techniques: spectroscopic; Astrophysics - Earth and Planetary Astrophysics

Domaines: Planète et Univers [physics]

Jeffrey Chilcote, Laurent Pueyo, Robert J. de Rosa, Jeffrey Vargas, Bruce Macintosh, et al.. 1-2.4 μm Near-IR Spectrum of the Giant Planet β Pictoris b Obtained with the Gemini Planet Imager. The Astronomical Journal, 2017, 153, ⟨10.3847/1538-3881/aa63e9⟩. ⟨insu-03692525⟩