As the Worlds Turn: Constraining Spin Evolution in the Planetary-Mass Regime

Abstract

To understand how planetary spin evolves and traces planet formation processes, we measure rotational line broadening in eight planetary-mass objects (PMOs) of various ages (1--800 Myr) using near-infrared high-resolution spectra from NIRSPEC/Keck. Combining these with published rotation rates, we compile 27 PMO spin velocities, 16 of which derive from our NIRSPEC/Keck program. Our data are consistent with spin velocities $v$ scaling with planetary radius $R$ as $v\propto 1/R$. We conclude that spin angular momentum is conserved as objects cool and contract over the sampled age range. The PMOs in our sample spin at rates that are approximately an order of magnitude below their break-up values, consistent with the hypothesis that they were spun down by magnetized circum-PMO disks (CPDs) during the formation era at ages $\lesssim$ a few Myr. There is a factor of 4--5 variation in spin velocity that has yet to be understood theoretically. It also remains to be seen whether spin evolves on timescales $\gtrsim$ 1 Gyr for PMOs, as it does for stars and high-mass brown dwarfs emitting magnetized winds.

arXiv commentaccepted to ApJ

References in corpus (88)

• A Non-Gray Theory of Extrasolar Giant Planets and Brown Dwarfs
• A giant planet imaged in the disk of the young star Beta Pictoris
• Precipitating Condensation Clouds in Substellar Atmospheres
• Molecfit: A general tool for telluric absorption correction. I. Method and application to ESO instruments
• The Evolution of L and T Dwarfs in Color-Magnitude Diagrams
• A self-consistent, absolute isochronal age scale for young moving groups in the solar neighbourhood
• Molecfit: A general tool for telluric absorption correction II. Quantitative evaluation on ESO-VLT X-Shooter spectra
• The Gemini Planet Imager Exoplanet Survey: Giant Planet and Brown Dwarf Demographics From 10-100 AU
• Neglected Clouds in T and Y Dwarf Atmospheres
• The fast spin-rotation of a young extrasolar planet
• Improved angular momentum evolution model for solar-like stars
• Imaging Extrasolar Giant Planets
• Fundamental Parameters and Spectral Energy Distributions of Young and Field Age Objects with Masses Spanning the Stellar to Planetary Regime
• The T Tauri Phase Down to Nearly Planetary Masses: Echelle Spectra of 82 Very Low Mass Stars and Brown Dwarfs
• Reflected Spectra and Albedos of Extrasolar Giant Planets I: Clear and Cloudy Atmospheres
• Population Properties of Brown Dwarf Analogs to Exoplanets
• A companion to AB Pic at the planet/brown dwarf boundary
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• Two Wide Planetary-Mass Companions to Solar-Type Stars in Upper Scorpius
• Discovery of a young planetary mass companion to the nearby M dwarf VHS J125601.92-125723.9
• HD 106906 b: A planetary-mass companion outside a massive debris disk
• A library of near-infrared integral field spectra of young M-L dwarfs
• Constraining the initial entropy of directly-detected exoplanets
• HD 203030B: an Unusually Cool Young Sub-Stellar Companion near the L/T Transition
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• Young "Dipper" Stars in Upper Sco and $\rho$ Oph Observed by K2
• Directly Imaged L-T Transition Exoplanets in the Mid-Infrared
• Three Wide Planetary-Mass Companions to FW Tau, ROXs 12, and ROXs 42B
• Near-infrared cross-dispersed spectroscopy of brown dwarf candidates in the Upper Sco association
• Characterization of exoplanets from their formation III: The statistics of planetary luminosities
• Direct Imaging and Spectroscopy of a Candidate Companion Below/Near the Deuterium-Burning Limit In The Young Binary Star System, ROXs 42B
• Spectroscopic rotational velocities of brown dwarfs
• Discovery of a Young Substellar Companion in Chamaeleon
• Accretion onto Planetary Mass Companions of Low-Mass Young Stars
• Planets Around Low-Mass Stars (PALMS). III. A Young Dusty L Dwarf Companion at the Deuterium-Burning Limit
• On the Terminal Rotation Rates of Giant Planets
• BANYAN. V. A Systematic All-Sky Survey for New Very Late-Type Low-Mass Stars and Brown Dwarfs in Nearby Young Moving Groups
• All-sky Co-moving Recovery Of Nearby Young Members. (ACRONYM) II: The Beta Pictoris Moving Group
• The Viewing Geometry of Brown Dwarfs Influences Their Observed Colours and Variability Properties
• Doppler Imaging of Exoplanets and Brown Dwarfs
• The slow spin of the young sub-stellar companion GQ Lupi b and its orbital configuration
• Physical Properties of Young Brown Dwarfs and Very Low-Mass Stars Inferred from High-Resolution Model Spectra
• CSI 2264: Characterizing Young Stars in NGC 2264 with Short-Duration, Periodic Flux Dips in their Light Curves
• The evolution of stars in the Taurus-Auriga T association
• Spectroscopic Confirmation of Young Planetary-Mass Companions on Wide Orbits
• Discovery of Rotational Modulations in the Planetary-Mass Companion 2M1207b: Intermediate Rotation Period and Heterogeneous Clouds in a Low Gravity Atmosphere
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• High Resolution 4.7 um Keck/NIRSPEC Spectra of Protostars. II: Detection of the 13CO Isotope in Icy Grain Mantles
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• KIC 8462852: Transit of a Large Comet Family
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• Evolution of Gas Giant Entropy During Formation by Runaway Accretion
• SIMP J013656.5+093347 is Likely a Planetary-Mass Object in the Carina-Near Moving Group
• A Model-Independent Mass and Moderate Eccentricity for $\beta$ Pic b
• Spitzer Variability Properties of Low-Gravity L Dwarfs
• Quasi-static contraction during runaway gas accretion onto giant planets
• Obliquity Constraints on an Extrasolar Planetary-Mass Companion
• The Planetary Accretion Shock. II. Grid of Post-Shock Entropies and Radiative Shock Efficiencies for Non-Equilibrium Radiation Transport
• Variability of the Lowest Mass Objects in the AB Doradus Moving Group
• Adaptive Optics imaging of VHS 1256-1257: A Low Mass Companion to a Brown Dwarf Binary System
• Shock-driven Accretion in Circumplanetary Disks: Observables and Satellite Formation
• Characterization of Low-mass, Wide-separation Substellar Companions to Stars in Upper Scorpius: Near-infrared Photometry and Spectroscopy
• The Radial and Rotational Velocities of PSO J318.5338$-$22.8603, a Newly Confirmed Planetary-Mass Member of the $\beta$ Pictoris Moving Group
• A universal spin-mass relation for brown dwarfs and planets
• The Hawaii Infrared Parallax Program. III. 2MASS J0249-0557 c: A Wide Planetary-mass Companion to a Low-mass Binary in the beta Pic Moving Group
• Cloud Atlas: Rotational Spectral Modulations and potential Sulfide Clouds in the Planetary-mass, Late T-type Companion Ross 458C
• Cloud Atlas: Rotational Modulations in the L/T Transition Brown Dwarf Companion HN Peg B
• The Young Substellar Companion ROXs 12 B: Near-Infrared Spectrum, System Architecture, and Spin-Orbit Misalignment
• Radial and rotational velocities of young brown dwarfs and very low-mass stars in the Upper Scorpius OB association and the rho Ophiuchi cloud core
• Rotation Periods of Young Brown Dwarfs: K2 Survey in Upper Scorpius
• Cloud Atlas: High-Contrast Time-Resolved Observations of Planetary-Mass Companions
• An ALMA Constraint on the GSC 6214-210 B Circum-Substellar Accretion Disk Mass
• Hot Start Giant Planets Form With Radiative Interiors
• ALMA Observations of the Young Substellar Binary System 2M1207
• Breaking the centrifugal barrier to giant planet contraction by magnetic disc braking
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• Cloud Atlas: Variability in and out of the Water Band in the Planetary-mass HD 203030B Points to Cloud Sedimentation in Low-gravity L Dwarfs
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• A Rotation Rate for the Planetary-Mass Companion DH Tau b
• The Prototypical Young L/T-Transition Dwarf HD 203030B Likely Has Planetary Mass
• Cloud Atlas: High-precision HST/WFC3/IR Time-Resolved Observations of Directly-Imaged Exoplanet HD106906b
• Spitzer Light Curves of the Young, Planetary-Mass TW Hya Members 2MASS J11193254-1137466AB and WISEA J114724.10-204021.3
• The Rotation-Disk Connection in Young Brown Dwarfs: Strong Evidence for Early Rotational Braking
• Mid-infrared characterization of the planetary-mass companion ROXs 42B b

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