Physical and orbital properties of Beta Pictoris b

Abstract

The intermediate-mass star Beta Pictoris is known to be surrounded by a structured edge-on debris disk within which a gas giant planet was discovered orbiting at 8-10 AU. The physical properties of Beta Pic b were previously inferred from broad and narrow-band 0.9-4.8 microns photometry. We used commissioning data of the Gemini Planet Imager (GPI) to obtain new astrometry and a low-resolution (R=35-39) J-band (1.12-1.35 microns) spectrum of the planet. We find that the planet has passed the quadrature. We constrain its semi-major axis to $\le$ 10 AU (90 % prob.) with a peak at 8.9+0.4-0.6 AU. The joint fit of the planet astrometry and the most recent radial velocity measurements of the star yields a planet's dynamical mass $\le$ 20 MJup (greater than 96 % prob.). The extracted spectrum of Beta Pic b is similar to those of young L1-1.5+1 dwarfs. We use the spectral type estimate to revise the planet luminosity to log(L/Lsun)=-3.90+-0.07. The 0.9-4.8 microns photometry and spectrum are reproduced for Teff=1650+-150 K and a log g lower than 4.7 dex by 12 grids of PHOENIX-based and LESIA atmospheric models. If we adopt the most recent system age estimate (21+-4 Myr), the bolometric luminosity and the constraints on the dynamical mass of Beta Pic b are only reproduced by warm- and hot-start tracks with initial entropies Si greater than 10.5 kB/baryon. Such initial conditions may result from an inefficient accretion shock and/or a planetesimal density at formation higher than in the classical core accretion model. Considering a younger age for the system or a conservative formation time for Beta Pic b does not change these conclusions.

arXiv comment4 pages, 4 figures, 2 tables. 4 online appendices. Accepted for publication in A&A letters

References in corpus (36)

• Evolutionary models for cool brown dwarfs and extrasolar giant planets. The case of HD 20945
• Evolutionary models for very-low-mass stars and brown dwarfs with dusty atmospheres
• Angular Differential Imaging: a Powerful High-Contrast Imaging Technique
• A giant planet imaged in the disk of the young star Beta Pictoris
• A probable giant planet imaged in the Beta Pictoris disk
• On the Luminosity of Young Jupiters
• Spectral and Photometric Diagnostics of Giant Planet Formation Scenarios
• A Near-Infrared Spectroscopic Study of Young Field Ultracool Dwarfs
• Solar System Abundances of the Elements
• A lithium depletion boundary age of 21 Myr for the Beta Pictoris moving group
• The Extremely Red, Young L Dwarf PSO J318-22: A Free-Floating Planetary-Mass Analog to Directly Imaged Young Gas-Giant Planets
• Orbital characterization of the βPictoris b giant planet
• Subtle Signatures of Multiplicity in Late-type Dwarf Spectra: The Unresolved M8.5 + T5 Binary 2MASS J03202839-0446358
• A library of near-infrared integral field spectra of young M-L dwarfs
• Constraining the initial entropy of directly-detected exoplanets
• The Directly Imaged Planet around the Young Solar Analog 1RXS J160929.1-210524: Confirmation of Common Proper Motion, Temperature and Mass
• Near-infrared cross-dispersed spectroscopy of brown dwarf candidates in the Upper Sco association
• The Gemini NICI Planet-Finding Campaign : Discovery of a Substellar L Dwarf Companion to the Nearby Young M Dwarf CD-35 2722
• A Combined VLT and Gemini Study of the Atmosphere of the Directly-Imaged Planet, beta Pictoris b
• The near-infrared spectral energy distribution of β Pictoris b
• Discovery of a Planetary-mass Companion to a Brown Dwarf in Taurus
• Deuterium Burning in Massive Giant Planets and Low-Mass Brown Dwarfs formed by Core-Nucleated Accretion
• Luminosity of young Jupiters revisited. Massive cores make hot planets
• Discovery of the Young L Dwarf WISE J1741102.78-464225.5
• First Results From VLT NACO Apodizing Phase Plate: 4-micron Images of the Exoplanet beta Pictoris b
• Physical Properties of Young Brown Dwarfs and Very Low-Mass Stars Inferred from High-Resolution Model Spectra
• Searching for companions down to 2 AU from beta Pictoris using the L'-band AGPM coronagraph on VLT/NACO
• Accurate Astrometry and Photometry of Saturated and Coronagraphic Point Spread Functions
• Magellan Adaptive Optics first-light observations of the exoplanet $\beta$ Pic b. I. Direct imaging in the far-red optical with MagAO+VisAO and in the near-IR with NICI
• Constrains on planets around beta Pic with Harps radial velocity data
• Near-infrared integral-field spectra of the planet/brown dwarf companion AB Pic b
• Near-Infrared Detection and Characterization of the Exoplanet HD 95086 b with the Gemini Planet Imager
• The Coolest Isolated Brown Dwarf Candidate Member of TWA
• New constraints on the formation and settling of dust in the atmospheres of young M and L dwarfs
• Planets around stars in young nearby associations *** radial Velocity searches: a feasibility study, and first results
• Independent confirmation of β Pictoris b imaging with NICI

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