AB Aurigae: Possible evidence of planet formation through the gravitational instability

Abstract

Recent observations of the protoplanetary disc surrounding AB Aurigae have revealed the possible presence of two giant planets in the process of forming. The young measured age of $1-4$Myr for this system allows us to place strict time constraints on the formation histories of the observed planets. Hence we may be able to make a crucial distinction between formation through core accretion (CA) or the gravitational instability (GI), as CA formation timescales are typically Myrs whilst formation through GI will occur within the first $\approx 10^4-10^5$yrs of disc evolution. We focus our analysis on the $4-13$M${}_{\mathrm{Jup}}$ planet observed at $R\approx 30$AU. We find CA formation timescales for such a massive planet typically exceed the system's age. The planet's high mass and wide orbit may instead be indicative of formation through GI. We use smoothed particle hydrodynamic simulations to determine the system's critical disc mass for fragmentation, finding $M_{\mathrm{d},\mathrm{crit}}=0.3$M${}_{\odot }$. Viscous evolution models of the disc's mass history indicate that it was likely massive enough to exceed $M_{\mathrm{d},\mathrm{crit}}$ in the recent past, thus it is possible that a young AB Aurigae disc may have fragmented to form multiple giant gaseous protoplanets. Calculations of the Jeans mass in an AB Aurigae-like disc find that fragments may initially form with masses $1.6-13.3$M${}_{\mathrm{Jup}}$, consistent with the planets which have been observed. We therefore propose that the inferred planets in the disc surrounding AB Aurigae may be evidence of planet formation through GI.

arXiv comment12 pages, 5 figures

References in corpus (86)

• Gaia Data Release 2. Summary of the contents and survey properties
• Direct Imaging of Multiple Planets Orbiting the Star HR 8799
• Disk Frequencies and Lifetimes in Young Clusters
• Protoplanetary Disks and Their Evolution
• Rapid planetesimal formation in turbulent circumstellar discs
• Streaming Instabilities in Protoplanetary Disks
• First Results from High Angular Resolution ALMA Observations Toward the HL Tau Region
• Nonlinear Outcome of Gravitational Instability in Cooling, Gaseous Disks
• Towards a Deterministic Model of Planetary Formation I: a Desert in the Mass and Semi Major Axis Distributions of Extra Solar Planets
• Images of a fourth planet orbiting HR 8799
• Using FU Orionis Outbursts to Constrain Self-Regulated Protostellar Disk Models
• Circumstellar Dust Disks in Taurus-Auriga: The Submillimeter Perspective
• A simple model for the evolution of the dust population in protoplanetary disks
• Coagulation, fragmentation and radial motion of solid particles in protoplanetary disks
• Discovery of a planetary-mass companion within the gap of the transition disk around PDS 70
• The outcome of protoplanetary dust growth: pebbles, boulders, or planetesimals? II. Introducing the bouncing barrier
• Ringed Substructure and a Gap at 1 AU in the Nearest Protoplanetary Disk
• On the Submillimeter Opacity of Protoplanetary Disks
• The Disk Substructures at High Angular Resolution Project (DSHARP): II. Characteristics of Annular Substructures
• The Gemini Planet Imager Exoplanet Survey: Giant Planet and Brown Dwarf Demographics From 10-100 AU
• Two accreting protoplanets around the young star PDS 70
• Can giant planets form by direct gravitational instability?
• Phantom: A smoothed particle hydrodynamics and magnetohydrodynamics code for astrophysics
• Disks ARound TTauri Stars with Sphere (DARTTS-S) I: Sphere / IRDIS Polarimetric Imaging of 8 prominent TTauri Disks
• Investigating fragmentation conditions in self-gravitating accretion discs
• Spiral Density Waves in a Young Protoplanetary Disk
• Protoplanetary Disk Turbulence Driven by the Streaming Instability: Linear Evolution and Numerical Methods
• Asymmetric features in the protoplanetary disk MWC758
• The Runts of the Litter: Why planets formed through gravitational instability can only be failed binary stars
• Protoplanetary disc evolution and dispersal: the implications of X-ray photoevaportion
• Retired A Stars and Their Companions: Exoplanets Orbiting Three Intermediate-Mass Subgiants
• Orbital and atmospheric characterization of the planet within the gap of the PDS 70 transition disk
• Spiral Arms in the Asymmetrically Illuminated Disk of MWC 758 and Constraints on Giant Planets
• Direct Imaging of Fine Structures in Giant Planet Forming Regions of the Protoplanetary Disk around AB Aurigae
• Pseudo-viscous modeling of self-gravitating discs and the formation of low mass ratio binaries
• Three radial gaps in the disk of TW Hydrae imaged with SPHERE
• Accelerated planetesimal growth in self-gravitating protoplanetary discs
• Retired A Stars and Their Companions. III. Comparing the Mass-Period Distributions of Planets Around A-Type Stars and Sun-Like Stars
• Dust Evolution in Protoplanetary Disks
• Adding particle collisions to the formation of asteroids and Kuiper belt objects via streaming instabilities
• Small vs large dust grains in transitional disks: do different cavity sizes indicate a planet?
• Formation of planets by tidal downsizing of giant planet embryos
• The Eccentric Cavity, Triple Rings, Two-Armed Spirals, and Double Clumps of the MWC 758 Disk
• 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
• Fragmentation of gravitationally unstable gaseous protoplanetary disks with radiative transfer
• Rapid inward migration of planets formed by gravitational instability
• The minimum mass for star formation, and the origin of binary brown dwarfs
• Radiative transfer and the energy equation in SPH simulations of star formation
• Direct detection of scattered light gaps in the transitional disk around HD 97048 with VLT/SPHERE
• Sub-arcsec imaging of the AB Aur molecular disk and envelope at millimeter wavelengths: a non Keplerian disk
• High-resolution simulations of planetesimal formation in turbulent protoplanetary discs
• Grain sedimentation inside giant planet embryos
• Towards a Population Synthesis Model of Objects formed by Self-Gravitating Disc Fragmentation and Tidal Downsizing
• The VLT/NaCo large program to probe the occurrence of exoplanets and brown dwarfs at wide orbits. IV. Gravitational instability rarely forms wide, giant planets
• Measuring Protoplanetary Disk Accretion with H I Pf-beta
• Planetesimal formation via fragmentation in self-gravitating protoplanetary discs
• The circumstellar disk of AB Aurigae: evidence for envelope accretion at late stages of star formation?
• Time-dependent models of the structure and evolution of self-gravitating protoplanetary discs
• Planet Formation in AB Aurigae: Imaging of the inner gaseous Spirals observed inside the Dust Cavity
• Rings and gaps in the disc around Elias 24 revealed by ALMA
• A Closer Look at the LkCa 15 Protoplanetary Disk
• Towards a population synthesis model of self-gravitating disc fragmentation and tidal downsizing II: The effect of fragment-fragment interactions
• CO gas inside the protoplanetary disk cavity in HD 142527: disk structure from ALMA
• Introducing a Hybrid Method of Radiative Transfer for Smoothed Particle Hydrodynamics
• Protoplanetary Disks as (Possibly) Viscous Disks
• Dust trapping by spiral arms in gravitationally unstable protostellar discs
• Possible evidence of ongoing planet formation in AB Aurigae. A showcase of the SPHERE/ALMA synergy
• The Jeans Mass as a Fundamental Measure of Self-Gravitating Disc Fragmentation and Initial Fragment Mass
• Millimeter observations and modeling of the AB Aurigae system
• Did Fomalhaut, HR 8799, and HL Tauri Form Planets via the Gravitational Instability? Placing Limits on the Required Disk Masses
• Formation of terrestrial planet cores inside giant planet embryos
• AB Aurigae Resolved: Evidence for Spiral Structure
• HD 169142 in the eyes of ZIMPOL/SPHERE
• Identifying and Analysing Protostellar Disc Fragments in Smoothed Particle Hydrodynamics Simulations
• The fragmentation criteria in local vertically stratified self-gravitating disk simulations
• Predicting the kinematic evidence of gravitational instability
• Massive discs around low-mass stars
• Physical and chemical structure of planet-forming disks probed by millimeter observations and modeling
• Tidal Downsizing Model. III. Planets from sub-Earths to Brown Dwarfs: structure and metallicity preferences
• The temporal requirements of directly observing self-gravitating spiral waves in protoplanetary discs with ALMA
• The Effect of Irradiation on the Jeans Mass in Fragmenting Self-Gravitating Protostellar Discs
• Fragmentation favoured in discs around higher mass stars
• Constraining the initial planetary population in the gravitational instability model
• Observing protoplanetary discs with the Square Kilometre Array -- I. Characterising pebble substructure caused by forming planets
• Theory of planet formation
• The observational impact of dust trapping in self-gravitating discs

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• Images of Embedded Jovian Planet Formation At A Wide Separation Around AB Aurigae
• Gravitational instability in a planet-forming disk
• SO and SiS Emission Tracing an Embedded Planet and Compact ${}^{12}$CO and ${}^{13}$CO Counterparts in the HD 169142 Disk
• Binary companions triggering fragmentation in self-gravitating discs
• Detection of Near-Infrared Water Ice at the Surface of the (pre)Transitional Disk of AB Aur: Informing Icy Grain Abundance, Composition, and Size
• Dynamical Data Mining Captures Disc-Halo Couplings that Structure Galaxies
• Orbital Migration of Protoplanets in a Marginally Gravitationally Unstable Disk. II. Migration, Merging, and Ejection
• The link between infall location, early disc size, and the fraction of self-gravitationally fragmenting discs
• Constraining protoplanetary disc mass using the GI wiggle
• Gravitational instability in planet-forming discs