Formation of TRAPPIST-1 and other compact systems

Abstract

TRAPPIST-1 is a nearby 0.08 M M-star, which was recently found to harbor a planetary system of at least seven Earth-mass planets, all within 0.1 au. The configuration confounds theorists as the planets are not easily explained by either in situ or migration models. In this Paper we present a scenario for the formation and orbital architecture of the TRAPPIST-1 system. In our model, planet formation starts at the H2O iceline, where pebble-size particles -- whose origin is the outer disk -- concentrate to trigger streaming instabilities. After their formation, planetary embryos quickly mature by pebble accretion. Planet growth stalls at Earth masses, where the planet's gravitational feedback on the disk keeps pebbles at bay. Planets are transported by Type I migration to the inner disk, where they stall at the magnetospheric cavity and end up in mean motion resonances. During disk dispersal, the cavity radius expands and the inner-most planets escape resonance. We argue that the model outlined here can also be applied to other compact systems and that the many close-in super-Earth systems are a scaled-up version of TRAPPIST-1. We also hypothesize that few close-in compact systems harbor giant planets at large distances, since they would have stopped the pebble flux from the outer disk.

8 pages, accepted for publication in A&A

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Cited by in corpus (123)

• The nature of the TRAPPIST-1 exoplanets
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• The New Generation Planetary Population Synthesis (NGPPS). IV. Planetary systems around low-mass stars
• The New Generation Planetary Population Synthesis (NGPPS). I. Bern global model of planet formation and evolution, model tests, and emerging planetary systems
• The nature and origins of sub-Neptune size planets
• A water budget dichotomy of rocky protoplanets from ${}^{26}$Al-heating
• Transport of CO in Protoplanetary Disks: Consequences of Pebble Formation, Settling, and Radial Drift
• Planetary system around the nearby M dwarf GJ 357 including a transiting, hot, Earth-sized planet optimal for atmospheric characterization
• The evolution of dust-disk sizes from a homogeneous analysis of 1-10 Myr-old stars
• The Near-Infrared Transmission Spectra of TRAPPIST-1 Planets b, c, d, e, f, and g and Stellar Contamination in Multi-Epoch Transit Spectra
• How planetary growth outperforms migration
• Temporal evolution of the high-energy irradiation and water content of TRAPPIST-1 exoplanets
• Revised mass-radius relationships for water-rich rocky planets more irradiated than the runaway greenhouse limit
• The First Habitable Zone Earth-sized Planet from TESS. I: Validation of the TOI-700 System
• Characterizing the variable dust permeability of planet-induced gaps
• The New Generation Planetary Population Synthesis (NGPPS). III. Warm super-Earths and cold Jupiters: A weak occurrence correlation, but with a strong architecture-composition link
• Rocky super-Earths or waterworlds: the interplay of planet migration, pebble accretion and disc evolution
• The evolution of dust in discs influenced by external photoevaporation
• A review of possible planetary atmospheres in the TRAPPIST-1 system
• Evidence for a high mutual inclination between the cold Jupiter and transiting super Earth orbiting $\pi$ Men
• Pebble-driven planet formation for TRAPPIST-1 and other compact systems
• Planet formation and migration near the silicate sublimation front in protoplanetary disks
• Pebbles versus Planetesimals: The case of Trappist-1
• The TRAPPIST-1 system: Orbital evolution, tidal dissipation, formation and habitability
• A Tale of Planet Formation: From Dust to Planets
• TRAPPIST-1: Global Results of the Spitzer Exploration Science Program {\it Red Worlds}
• Growth after the streaming instability: from planetesimal accretion to pebble accretion
• Efficient planet formation by pebble accretion in ALMA rings
• Two temperate super-Earths transiting a nearby late-type M dwarf
• Bright Opportunities for Atmospheric Characterization of Small Planets: Masses and Radii of K2-3 b, c, d and GJ3470 b from Radial Velocity Measurements and Spitzer Transits
• Diverse outcomes of planet formation and composition around low-mass stars and brown dwarfs
• The first multi-dimensional view of mass loss from externally FUV irradiated protoplanetary discs
• Prevalent externally-driven protoplanetary disc dispersal as a function of the galactic environment
• Interior characterization in multiplanetary systems: TRAPPIST-1
• Physical constraints for the evolution of life on exoplanets
• The New Generation Planetary Population Synthesis (NGPPS). V. Predetermination of planet types in global core accretion models
• Cometary impactors on the TRAPPIST-1 planets can destroy all planetary atmospheres and rebuild secondary atmospheres on planets f, g, h
• Dry or water world? How the water contents of inner sub-Neptunes constrain giant planet formation and the location of the water ice line
• A Lagrangian Model for Dust Evolution in Protoplanetary Disks: Formation of Wet and Dry Planetesimals at Different Stellar Masses
• Where can a Trappist-1 planetary system be produced?
• A Balanced Budget View on Forming Giant Planets by Pebble Accretion
• Pebble dynamics and accretion onto rocky planets. I. Adiabatic and convective models
• Formation of moon systems around giant planets: Capture and ablation of planetesimals as foundation for a pebble accretion scenario
• A dusty origin for the correlation between protoplanetary disc accretion rates and dust masses
• The Galilean Satellites Formed Slowly from Pebbles
• The Exoplanet Population Observation Simulator. II -- Population Synthesis in the Era of Kepler
• Contribution of the core to the thermal evolution of sub-Neptunes
• Exoplanet characterisation in the longest known resonant chain: the K2-138 system seen by HARPS
• Impacts of dust feedback on a dust ring induced by a planet in a protoplanetary disk
• The evolution of protoplanetary discs in star formation and feedback simulations
• A Universal Break in the Planet-to-Star Mass-Ratio Function of Kepler MKG stars
• An upper limit on late accretion and water delivery in the Trappist-1 exoplanet system
• Mutual Orbital Inclinations Between Cold Jupiters and Inner Super-Earths
• The multiplicity distribution of Kepler's exoplanets
• Efficiency of radial transport of ices in protoplanetary disks probed with infrared observations: the case of CO${}_2$
• Proplyds in the Flame Nebula NGC 2024
• Massive discs around low-mass stars
• Super-Earths and Earth-like Exoplanets
• HD 23472: A multi-planetary system with three super-Earths and two potential super-Mercuries
• The dynamics of the TRAPPIST-1 system in the context of its formation
• Planet formation via pebble accretion in externally photoevaporating discs
• A roadmap for the atmospheric characterization of terrestrial exoplanets with JWST
• Do the TRAPPIST-1 Planets Have Hydrogen-rich Atmospheres?
• How to make giant planets via pebble accretion
• Near-infrared transmission spectrum of TRAPPIST-1 h using Hubble WFC3 G141 observations
• Implications of atmospheric nondetections for Trappist-1 inner planets on atmospheric retention prospects for outer planets
• The influence of the environment on the spin evolution of low-mass stars. I. External photoevaporation of circumstellar disks
• Three Pathways for Observed Resonant Chains
• TOI-216: Resonant Constraints on Planet Migration
• Kepler-167e as a Probe of the Formation Histories of Cold Giants with Inner Super-Earths
• The importance of thermal torques on the migration of planets growing by pebble accretion
• Resolved millimeter-dust continuum cavity around the very low mass young star CIDA 1
• The imprint of X-ray photoevaporation of planet-forming discs on the orbital distribution of giant planets
• Warm millimetre dust in protoplanetary discs near massive stars
• Energy Dissipation in the Upper Atmospheres of Trappist-1 Planets
• Influence of migration models and thermal torque on planetary growth in the pebble accretion scenario
• Influences of three-dimensional gas flow induced by protoplanets on pebble accretion --$\mathrm{I}$. shear regime
• Habitable planet formation around low-mass stars: Rapid accretion, rapid debris removal and the essential contribution of external giants
• Water delivery to the TRAPPIST-1 planets
• TRAPPIST-1: Dynamical analysis of the transit-timing variations and origin of the resonant chain
• Chemical modeling of Orion Nebula Cluster disks: evidence for massive, compact gas disks with ISM-like gas-to-dust ratios
• Growth and evolution of satellites in a Jovian massive disc
• Solving for the 2D Water Snowline with Hydrodynamic Simulations. Emergence of gas outflow, water cycle and temperature plateau
• Mercury as the relic of Earth and Venus' outward migration
• The tidal parameters of TRAPPIST-1 b and c
• Forming the Trappist-1 system in two steps during the recession of the disc inner edge
• Long-term tidal evolution of the TRAPPIST-1 system
• The growth of super-Earths: the importance of a self-consistent treatment of disc structures and pebble accretion
• Growth after the streaming instability: The radial distance dependence of the planetary growth
• Filling in the Gaps: Can Gravitationally Unstable Discs Form the Seeds of Gas Giant Planets?
• A Pluto--Charon Sonata: Dynamical Limits on the Masses of the Small Satellites
• Herschel Observations of Disks around Late-type Stars
• Multiverse Predictions for Habitability: Number of Potentially Habitable Planets
• The Terrestrial Planet Formation around M Dwarfs: In-situ, Inward Migration or Reversed Migration
• Dynamical rearrangement of super-Earths during disk dispersal II. Assessment of the magnetospheric rebound model for planet formation scenarios
• Transit Duration Variations in Multi-Planet Systems
• Photoevaporation of the Jovian circumplanetary disk I. Explaining the orbit of Callisto and the lack of outer regular satellites
• Rapid-then-slow migration reproduces mass distribution of TRAPPIST-1 system
• Formation of multiple-planet systems in resonant chains around M dwarfs
• Illuminating a tadpole's metamorphosis II: observing the on-going transformation with ALMA
• Planet formation and disk mass dependence in a pebble-driven scenario for low mass stars
• Composition constraints of the TRAPPIST-1 planets from their formation
• MINDS. Strong oxygen depletion in the inner regions of a very low-mass star disk?
• Water transport throughout the TRAPPIST-1 system: the role of planetesimals
• Searching for a cometary belt around Trappist-1 with ALMA
• A formation pathway for terrestrial planets with moderate water content involving atmospheric-volatile recycling
• Accretion of aerodynamically large pebbles
• Pebble accretion in self-gravitating protostellar discs
• Tidally Heated Sub-Neptunes, Refined Planetary Compositions, and Confirmation of a Third Planet in the TOI-1266 System
• The evolution of the flux-size relationship in protoplanetary discs by viscous evolution and radial pebble drift
• Constraining Planetary Formation Models Using Conditional Occurrences of Various Planet Types
• Forming equal mass planetary binaries via pebble accretion
• From CO${}_2$- to H${}_2$O-dominated atmospheres and back -- How mixed outgassing changes the volatile distribution in magma oceans around M dwarf stars
• The extremely truncated circumstellar disc of V410 X-ray 1: a precursor to TRAPPIST-1?
• Origin of compact exoplanetary systems during disk infall
• Forming Earth-like and Low-Mass Rocky Exoplanets Through Pebble and Planetesimal Accretion
• Formation of super-Earths in icy dead zones around low-mass stars
• Predicting the Dominant Formation Mechanism of Multi-Planetary Systems
• The California Legacy Survey III. On The Shoulders of (Some) Giants: The Relationship between Inner Small Planets and Outer Massive Planets
• An Evolving Cosmic Shoreline and Sandbar Bounding the Rocky Airless Valley
• Spectra of Earth-like exoplanets with different rotation periods
• Rapid Formation of Super-Earths Around Low-Mass Stars