Intra-system uniformity: a natural outcome of dynamical sculpting

Abstract

There is evidence that exoplanet systems display intra-system uniformity in mass, radius, and orbital spacing (like ``peas in a pod'') when compared with the system-to-system variations of planetary systems. This has been interpreted as the outcome of the early stages of planet formation, indicative of a picture in which planets form at characteristic mass scales with uniform separations. In this paper, we argue instead that intra-system uniformity in planet sizes and orbital spacings likely arose from the dynamical sculpting of initially-overly-packed planetary systems (in other words, the giant impact phase). With a suite of $N$-body simulations, we demonstrate that systems with random initial masses and compact planet spacings naturally develop intra-system uniformity, in quantitative agreement with observations, due to collisions between planets. Our results suggest that the pre-giant impact planet mass distribution is fairly wide and provide evidence for the prevalence of dynamical sculpting in shaping the observed population of exoplanets.

arXiv comment6 pages, 5 figures. Accepted for publication in MNRAS Letters

References in corpus (41)

• The false positive rate of Kepler and the occurrence of planets
• REBOUND: An open-source multi-purpose N-body code for collisional dynamics
• Characteristics of planetary candidates observed by Kepler, II: Analysis of the first four months of data
• Architecture and Dynamics of Kepler's Candidate Multiple Transiting Planet Systems
• Architecture of Kepler's Multi-transiting Systems: II. New investigations with twice as many candidates
• IAS15: A fast, adaptive, high-order integrator for gravitational dynamics, accurate to machine precision over a billion orbits
• Photoevaporation of protoplanetary discs II: evolutionary models and observable properties
• WHFast: A fast and unbiased implementation of a symplectic Wisdom-Holman integrator for long term gravitational simulations
• Breaking the Chains: Hot Super-Earth systems from migration and disruption of compact resonant chains
• The California-Kepler Survey V. Peas in a Pod: Planets in a Kepler Multi-planet System are Similar in Size and Regularly Spaced
• Eccentricity from transit photometry: small planets in Kepler multi-planet systems have low eccentricities
• Breeding Super-Earths and Birthing Super-Puffs in Transitional Disks
• Testing In Situ Assembly with the Kepler Planet Candidate Sample
• Probabilistic Mass-Radius Relationship for Sub-Neptune-Sized Planets
• Densities and Eccentricities of 139 Kepler Planets from Transit Time Variations
• To Cool is to Accrete: Analytic Scalings for Nebular Accretion of Planetary Atmospheres
• Kepler Planet Masses and Eccentricities from TTV Analysis
• Kepler Multi-Planet Systems Exhibit Unexpected Intra-system Uniformity in Mass and Radius
• The Formation of Super-Earths and Mini-Neptunes with Giant Impacts
• Hybrid Symplectic Integrators for Planetary Dynamics
• Architectures of Exoplanetary Systems. I: A Clustered Forward Model for Exoplanetary Systems around Kepler's FGK Stars
• Comparing HARPS and Kepler surveys: The alignment of multiple-planet systems
• Are Planetary Systems Filled to Capacity? A Study Based on Kepler Results
• The (In)Stability of Planetary Systems
• The stability of tightly-packed, evenly-spaced systems of Earth-mass planets orbiting a Sun-like star
• Accounting for Incompleteness due to Transit Multiplicity in Kepler Planet Occurrence Rates
• The Exoplanet Radius Valley from Gas-driven Planet Migration and Breaking of Resonant Chains
• Atmospheric mass loss due to giant impacts: the importance of the thermal component for hydrogen-helium envelopes
• The HARPS search for southern extra-solar planets. XXXVI. Eight HARPS multi-planet systems hosting 20 super-Earth and Neptune-mass companions
• Architectures of Compact Super-Earth Systems Shaped by Instabilities
• The New Generation Planetary Population Synthesis (NGPPS). VI. Introducing KOBE: Kepler Observes Bern Exoplanets. Theoretical perspectives on the architecture of planetary systems: Peas in a pod
• The Kepler Peas in a Pod Pattern is Astrophysical
• On the patterns observed in Kepler multi-planet systems
• Energy Optimization in Extrasolar Planetary Systems: The Transition from Peas-in-a-Pod to Runaway Growth
• Forming Diverse Super-Earth Systems in Situ
• Formation of compact systems of super-Earths via dynamical instabilities and giant impacts
• Peas in a Pod? Radius correlations in Kepler multi-planet systems
• The "Breaking The Chains" migration model for super-Earths formation: the effect of collisional fragmentation
• Pairwise Tidal Equilibrium States and the Architecture of Extrasolar Planetary Systems
• How Close are Compact Multi-Planet Systems to the Stability Limit?
• Generalized Peas-in-a-Pod: Extending Intra-System Mass Uniformity to Non-TTV Systems via the Gini Index

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• The GAPS Programme at TNG. LIX. A characterisation study of the $\sim$300 Myr old multi-planetary system orbiting the star BD+40 2790 (TOI-2076)
• Close-in compact super-Earth systems emerging from resonant chains: slow destabilization by unseen remnants of formation
• Diversities and similarities exhibited by multi-planetary systems and their architectures: I. Orbital spacings
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