The Effect of Protoplanetary Disk Cooling Times on the Formation of Gas Giant Planets by Gravitational Instability

Abstract

Observational evidence exists for the formation of gas giant planets on wide orbits around young stars by disk gravitational instability, but the roles of disk instability and core accretion for forming gas giants on shorter period orbits are less clear. The controversy extends to population synthesis models of exoplanet demographics and to hydrodynamical models of the fragmentation process. The latter refers largely to the handling of radiative transfer in three dimensional (3D) hydrodynamical models, which controls heating and cooling processes in gravitationally unstable disks, and hence dense clump formation. A suite of models using the $\beta$ cooling approximation is presented here. The initial disks have masses of 0.091 $M_{\odot }$ and extend from 4 to 20 AU around a 1 $M_{\odot }$ protostar. The initial minimum Toomre $Q_i$ values range from 1.3 to 2.7, while $\beta$ ranges from 1 to 100. We show that the choice of $Q_i$ is equal in importance to the $\beta$ value assumed: high $Q_i$ disks can be stable for small $\beta$, when the initial disk temperature is taken as a lower bound, while low $Q_i$ disks can fragment for high $\beta$. These results imply that the evolution of disks toward low $Q_i$ must be taken into account in assessing disk fragmentation possibilities, at least in the inner disk, i.e., inside about 20 AU. The models suggest that if low $Q_i$ disks can form, there should be an as yet largely undetected population of gas giants orbiting G dwarfs between about 6 AU and 16 AU.

40 pages, 10 figures, 1 table, accepted by ApJ

References in corpus (38)

• Direct Imaging of Multiple Planets Orbiting the Star HR 8799
• One or more bound planets per Milky Way star from microlensing observations
• Modeling Collapse and Accretion in Turbulent Gas Clouds: Implementation and Comparison of Sink Particles in AMR and SPH
• Spiral Density Waves in a Young Protoplanetary Disk
• Structure and evolution of pre-main sequence circumstellar disks
• Towards Chemical Constraints on Hot Jupiter Migration
• The Two Modes of Gas Giant Planet Formation
• Exploring Exoplanet Populations with NASA's Kepler Mission
• A Spitzer view of protoplanetary disks in the gamma Velorum cluster
• Protoplanetary disk masses from CO isotopologues line emission
• On the formation of planetary systems via oligarchic growth in thermally evolving viscous discs
• Fragmentation of gravitationally unstable gaseous protoplanetary disks with radiative transfer
• The Thermal Regulation of Gravitational Instabilities in Protoplanetary Disks III. Simulations with Radiative Cooling and Realistic Opacities
• The Hot Inner Disk of FU Ori
• Numerical requirements for simulations of self gravitating and non-self gravitating disks
• Spatially Resolved Magnetic Field Structure in the Disk of a T Tauri Star
• Numerical Convergence in Smoothed Particle Hydrodynamics
• Planet Formation with Migration
• Testing Disk Instability Models for Giant Planet Formation
• Gravitational Instabilities, Chondrule Formation, and the FU Orionis Phenomenon
• On the reliability of protostellar disc mass measurements and the existence of fragmenting discs
• The Thermal Regulation of Gravitational Instabilities in Protoplanetary Disks. IV. Simulations with Envelope Irradiation
• Discovery of a Substellar Companion to the Nearby Debris Disk Host HR 2562
• Effects of radiation transfer on the structure of self-gravitating disks, their fragmentation and evolution of the fragments
• 3D Radiative Hydrodynamics for Disk Stability Simulations: A Proposed Testing Standard and New Results
• Protoplanetary Disk Masses in the Young NGC 2024 Cluster
• Viscosity prescription for gravitationally unstable accretion disks
• The Dynamical Fate of Self-Gravitating Disc Fragments After Tidal Downsizing
• Formation of Super-Earth Mass Planets at 125-250 AU from a Solar-type Star
• Flux-Limited Diffusion Approximation Models of Giant Planet Formation by Disk Instability
• Positive metallicity correlation for coreless giant planets
• Metal loading of giant gas planets
• A general hybrid radiation transport scheme for star formation simulations on an adaptive grid
• Self-gravitating disc candidates around massive young stars
• A $\sim$32-70 K formation temperature range for the ice grains agglomerated by comet 67P/Churyumov-Gerasimenko
• The dynamical evolution of low-mass hydrogen-burning stars, brown dwarfs and planetary-mass objects formed through disc fragmentation
• Fragmentation of protoplanetary disks around M-dwarfs
• Orbital Circularization of a Planet Accreting Disk Gas: Formation of Distant Jupiters in Circular Orbits based on Core Accretion Model

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• Flux-Limited Diffusion Approximation Models of Giant Planet Formation by Disk Instability. II. Quadrupled Spatial Resolution
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