The Effect of the Approach to Gas Disk Gravitational Instability on the Rapid Formation of Gas Giant Planets

Abstract

Observational evidence suggests that gas disk instability may be responsible for the formation of at least some gas giant exoplanets, particularly massive or distant gas giants. With regard to close-in gas giants, Boss (2017) used the $\beta$ cooling approximation to calculate hydrodynamical models of inner gas disk instability, finding that provided disks with low values of the initial minimum Toomre stability parameter (i.e., $Q_i<2$ inside 20 au) form, fragmentation into self-gravitating clumps could occur even for $\beta$ as high as 100 (i.e., extremely slow cooling). Those results implied that the evolution of disks toward low $Q_i$ must be taken into account. This paper presents such models: initial disk masses of 0.091 $M_{\odot }$ extending from 4 to 20 au around a 1 $M_{\odot }$ protostar, with a range (1 to 100) of $\beta$ cooling parameters, the same as in Boss (2017), but with all the disks starting with $Q_i=2.7$, i.e., gravitationally stable, and allowed to cool from their initial outer disk temperature of 180 K to as low as 40 K. All the disks eventually fragment into at least one dense clump. The clumps were again replaced by virtual protoplanets (VPs) and the masses and orbits of the resulting ensemble of VPs compare favorably with those of Boss (2017), supporting the claim that disk instability can form gas giants rapidly inside 20 au, provided that sufficiently massive protoplanetary disks exist.

24 pages, 2 tables, 8 figures, in press, ApJ

References in corpus (26)

• Two accreting protoplanets around the young star PDS 70
• Towards Chemical Constraints on Hot Jupiter Migration
• The Two Modes of Gas Giant Planet Formation
• The Disk Substructures at High Angular Resolution Project (DSHARP): III. Spiral Structures in the Millimeter Continuum of the Elias 27, IM Lup, and WaOph 6 Disks
• Evidence of an Upper Bound on the Masses of Planets and its Implications for Giant Planet Formation
• Can giant planets form by gravitational fragmentation of discs?
• Numerical requirements for simulations of self gravitating and non-self gravitating disks
• High resolution millimetre imaging of the CI Tau protoplanetary disc - a massive ensemble of protoplanets from 0.1 - 100 au
• Observational evidence for two distinct giant planet populations
• Towards a population synthesis model of self-gravitating disc fragmentation and tidal downsizing II: The effect of fragment-fragment interactions
• Planet Formation with Migration
• Spiral Arms in Disks: Planets or Gravitational Instability?
• A search for accreting young companions embedded in circumstellar disks: High-contrast H$\alpha$ imaging with VLT/SPHERE
• Convergence of the critical cooling rate for protoplanetary disk fragmentation achieved; the key role of numerical dissipation of angular momentum
• The ALMA early science view of FUor/EXor objects - V: continuum disc masses and sizes
• Properties and occurrence rates of $Kepler$ exoplanet candidates as a function of host star metallicity from the DR25 catalog
• Dust traps in the protoplanetary disc MWC 758: two vortices produced by two giant planets?
• The fragmentation criteria in local vertically stratified self-gravitating disk simulations
• Connecting substellar and stellar formation. The role of the host star's metallicity
• The Dynamical Fate of Self-Gravitating Disc Fragments After Tidal Downsizing
• ALMA observations of Elias 2-24: a protoplanetary disk with multiple gaps in the Ophiuchus Molecular Cloud
• On the diversity in mass and orbital radius of giant planets formed via disk instability
• The Maximum Mass Solar Nebula and the early formation of planets
• The Effect of Protoplanetary Disk Cooling Times on the Formation of Gas Giant Planets by Gravitational Instability
• Multiple Populations of Extrasolar Gas Giants
• Efficient radiative transfer techniques in hydrodynamic simulations

Cited by in corpus (5)

• Observations of Protoplanetary Disk Structures
• Three-dimensional transport of solids in a protoplanetary disk containing a growing giant planet
• Flux-Limited Diffusion Approximation Models of Giant Planet Formation by Disk Instability. II. Quadrupled Spatial Resolution
• The Effect of the Approach to Gas Disk Gravitational Instability on the Rapid Formation of Gas Giant Planets. II. Quadrupled Spatial Resolution
• Giant planet formation via pebble accretion across different stellar masses