2MASS J13243553+6358281 is an Early T-Type Planetary-Mass Object in the AB Doradus Moving Group

Abstract

We present new radial velocity and trigonometric parallax measurements indicating that the unusually red and photometrically variable T2 dwarf 2MASS J13243553+6358281 is a member of the young (~150 Myr) AB Doradus moving group based on its space velocity. We estimate its model-dependent mass in the range 11-12 $M_{\mathrm{Jup}}$ at the age of the AB Doradus moving group, and its trigonometric parallax distance of 12.7 $\pm$ 1.5 pc makes it one of the nearest known isolated planetary-mass objects. The unusually red continuum of 2MASS J13243553+6358281 in the near-infrared was previously suspected to be caused by an unresolved L+T brown dwarf binary, although it was never observed with high-spatial resolution imaging. This new evidence of youth suggests that a low surface gravity may be sufficient to explain this peculiar feature. Using the new parallax we find that its absolute $J$-band magnitude is ~0.4 mag fainter than equivalent-type field brown dwarfs, suggesting that the binary hypothesis is unlikely. The fundamental properties of 2MASS J13243553+6358281 follow the spectral type sequence of other known high-likelihood members of the AB Doradus moving group. The effective temperature of 2MASS J13243553+6358281 provides the first precise constraint on the L/T transition at a known young age, and indicates that it happens at a temperature of ~1150 K at ~150 Myr, compared to ~1250 K for field brown dwarfs.

9 pages, 4 figures, 1 table. Accepted for publication in the Astrophysical Journal Letters

References in corpus (20)

• Direct Imaging of Multiple Planets Orbiting the Star HR 8799
• The Evolution of L and T Dwarfs in Color-Magnitude Diagrams
• Gaia Data Release 1: Astrometry - one billion positions, two million proper motions and parallaxes
• Meeting the Cool Neighbors. IX. The Luminosity Function of M7-L8 Ultracool Dwarfs in the Field
• Population Properties of Brown Dwarf Analogs to Exoplanets
• The Hawaii Infrared Parallax Program. II. Young Ultracool Field Dwarfs
• Discovery of a young planetary mass companion to the nearby M dwarf VHS J125601.92-125723.9
• Discovery of 11 New T Dwarfs in the Two Micron All-Sky Survey, Including a Possible L/T Transition Binary
• HD 203030B: an Unusually Cool Young Sub-Stellar Companion near the L/T Transition
• A Cross-Match of 2MASS and SDSS: Newly-Found L and T Dwarfs and an Estimate of the Space Densitfy of T Dwarfs
• Discovery of a wide planetary-mass companion to the young M3 star GU Psc
• All-sky Co-moving Recovery Of Nearby Young Members. (ACRONYM) II: The Beta Pictoris Moving Group
• LACEwING: A New Moving Group Analysis Code
• SIMP J013656.5+093347 is Likely a Planetary-Mass Object in the Carina-Near Moving Group
• Simultaneous, Multi-Wavelength Variability Characterization of the Free-Floating Planetary Mass Object PSO J318.5-22
• WISEA J114724.10-204021.3: A Free-Floating Planetary Mass Member of the TW Hya Association
• Variability of the Lowest Mass Objects in the AB Doradus Moving Group
• The Nearest Isolated Member of the TW Hydrae Association is a Giant Planet Analog
• Weather on Other Worlds. III. A Survey for T Dwarfs with High Amplitude Optical Variability
• A search for photometric variability in the young T3.5 planetary-mass companion GU Psc b

Cited by in corpus (24)

• The Field Substellar Mass Function Based on the Full-sky 20-pc Census of 525 L, T, and Y Dwarfs
• Let the Great World Spin: Revealing the Stormy, Turbulent Nature of Young Giant Exoplanet Analogs with the Spitzer Space Telescope
• The SPHINX M-dwarf Spectral Grid. I. Benchmarking New Model Atmospheres to Derive Fundamental M-Dwarf Properties
• The GJ 504 system revisited. Combining interferometric, radial velocity, and high contrast imaging data
• The Hawaii Infrared Parallax Program. V. New T-Dwarf Members and Candidate Members of Nearby Young Moving Groups
• COol Companions ON Ultrawide orbiTS (COCONUTS). I. A High-Gravity T4 Benchmark around an Old White Dwarf and A Re-Examination of the Surface-Gravity Dependence of the L/T Transition
• Cloud Atlas: Rotational Spectral Modulations and potential Sulfide Clouds in the Planetary-mass, Late T-type Companion Ross 458C
• On the Detection of Exomoons Transiting Isolated Planetary-Mass Objects
• Emission line variability of young 10-30 Mjup companions : I. The case of GQ Lup b and GSC 06214-00210 b
• Detection of new strongly variable brown dwarfs in the L/T transition
• The Oceanus Moving Group: A New 500 Myr-Old Host for the Nearest Brown Dwarf
• Redder than Red: Discovery of an Exceptionally Red L/T Transition Dwarf
• WEIRD: Wide-orbit Exoplanet search with InfraRed Direct imaging
• A Census of the 32 Ori Association with Gaia
• Parallaxes of Cool Objects with WISE: Filling in for Gaia
• Rotation and Abundances of the Benchmark Brown Dwarf HD 33632 Ab from Keck/KPIC High-resolution Spectroscopy
• Direct-imaging Discovery of a Substellar Companion Orbiting the Accelerating Variable Star, HIP 39017
• A Near-infrared Variability Survey of Young Planetary-mass Objects
• Ultracool Dwarfs Observed with the Spitzer Infrared Spectrograph. I. An Accurate Look at the L-to-T Transition at $\sim$300 Myr from Optical through Mid-infrared Spectrophotometry
• New Candidates for Planetary-mass Brown Dwarfs in IC 348
• The Brown Dwarf Kinematics Project (BDKP). V. Radial and Rotational Velocities of T Dwarfs from Keck/NIRSPEC High-Resolution Spectroscopy
• Ross 19B: An Extremely Cold Companion Discovered via the Backyard Worlds: Planet 9 Citizen Science Project
• Disentangling the Signatures of Blended-Light Atmospheres in L/T Transition Brown Dwarfs
• A planetary-mass candidate imaged in the Young Suns Exoplanet Survey