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.

6 pages, 5 figures. Accepted for publication in MNRAS Letters

References in corpus (12)

• Photoevaporation of protoplanetary discs II: evolutionary models and observable properties
• Kepler Multi-Planet Systems Exhibit Unexpected Intra-system Uniformity in Mass and Radius
• Hybrid Symplectic Integrators for Planetary Dynamics
• 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
• 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
• Formation of compact systems of super-Earths via dynamical instabilities and giant impacts
• 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

Cited by in corpus (11)

• TESS Investigation -- Demographics of Young Exoplanets (TI-DYE) II: a second giant planet in the 17-Myr system HIP 67522
• Orbital Architectures of Kepler Multis From Dynamical Instabilities
• The instability mechanism of compact multiplanet systems
• Enhanced Size Uniformity for Near-resonant Planets
• Plausibility of Capture into High-Obliquity States for Exoplanets in the M Dwarf Habitable Zone
• Planets similar in size are often dissimilar in interior
• 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
• On the Ordering of Exoplanet Systems
• Re-accretion of Giant Impact Ejecta Can Drive Significant Atmospheric Erosion on Terrestrial Planets