The New Generation Planetary Population Synthesis (NGPPS). V. Predetermination of planet types in global core accretion models

Abstract

State-of-the-art planet formation models are now capable of accounting for the full spectrum of known planet types. This comes at the cost of increasing complexity of the models, which calls into question whether established links between their initial conditions and the calculated planetary observables are preserved. In this paper, we take a data-driven approach to investigate the relations between clusters of synthetic planets with similar properties and their formation history. We trained a Gaussian Mixture Model on typical exoplanet observables computed by a global model of planet formation to identify clusters of similar planets. We then traced back the formation histories of the planets associated with them. Using cluster affiliation as labels, we trained a Random Forest classifier to predict planet species from properties of the originating protoplanetary disk. Without presupposing any planet types, we identified four distinct classes in our synthetic population. They roughly correspond to the observed populations of (sub-)Neptunes, giant planets, and (super-)Earths, plus an additional unobserved class we denote as "icy cores". These groups emerge already within the first 0.1 Myr of the formation phase and are predicted from disk properties with an overall accuracy of >90%. The most reliable predictors are the initial orbital distance of planetary nuclei and the total planetesimal mass available. Giant planets form only in a particular region of this parameter space that is in agreement with purely analytical predictions. Including N-body interactions between the planets decreases the predictability, especially for sub-Neptunes that frequently undergo giant collisions and turn into super-Earths. The impact of gravitational interactions highlights the need for N-body integrators for realistic predictions of systems of low-mass planets. (abridged)

21 pages, 16 figures. Accepted for publication in Astronomy & Astrophysics

References in corpus (20)

• New evolutionary models for pre-main sequence and main sequence low-mass stars down to the hydrogen-burning limit
• Protoplanetary Disk Structures in Ophiuchus
• Growth Model Interpretation of Planet Size Distribution
• Models of the in situ formation of detected extrasolar giant planets
• Planetary population synthesis coupled with atmospheric escape: a statistical view of evaporation
• The Exoplanet Mass-Ratio Function from the MOA-II Survey: Discovery of a Break and Likely Peak at a Neptune Mass
• Hints for a Turnover at the Snow Line in the Giant Planet Occurrence Rate
• Close-in planetesimal formation by pile-up of drifting pebbles
• The New Generation Planetary Population Synthesis (NGPPS). IV. Planetary systems around low-mass stars
• Formation of planetary systems by pebble accretion and migration: Growth of gas giants
• Planet-planet scattering in planetesimal disks
• Planet population synthesis driven by pebble accretion in cluster environments
• CSI 2264: Investigating rotation and its connection with disk accretion in the young open cluster NGC 2264
• Microlensing Results Challenge the Core Accretion Runaway Growth Scenario for Gas Giants
• The mass-radius relationship from solar-type stars to terrestrial planets: a review
• Planetesimal Population Synthesis: Pebble Flux Regulated Planetesimal Formation
• 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
• Transiting Planets near the Snow Line from Kepler. I. Catalog
• Earths in Other Solar Systems N-body simulations: the Role of Orbital Damping in Reproducing the Kepler Planetary Systems
• Bridging the Planet Radius Valley: Stellar Clustering as a Key Driver for Turning Sub-Neptunes into Super-Earths

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