A framework for the architecture of exoplanetary systems. II. Nature versus nurture: Emergent formation pathways of architecture classes

Abstract

In the first paper of this series, we proposed a model-independent framework for characterising the architecture of planetary systems at the system level. There are four classes of planetary system architecture: similar, mixed, anti-ordered, and ordered. In this paper, we investigate the formation pathways leading to these four architecture classes. To understand the role of nature versus nurture in sculpting the final (mass) architecture of a system, we apply our architecture framework to synthetic planetary systems -- formed via core-accretion -- using the Bern model. General patterns emerge in the formation pathways of the four architecture classes. Almost all planetary systems emerging from protoplanetary disks whose initial solid mass was less than one Jupiter mass are similar. Systems emerging from heavier disks may become mixed, anti-ordered, or ordered. Increasing dynamical interactions (planet-planet, planet-disk) tends to shift a system's architecture from mixed to anti-ordered to ordered. Our model predicts the existence of a new metallicity-architecture correlation. Similar systems have very high occurrence around low-metallicity stars. The occurrence of the anti-ordered and ordered classes increases with increasing metallicity. The occurrence of mixed architecture first increases and then decreases with increasing metallicity. In our synthetic planetary systems, the role of nature is disentangled from the role of nurture. Nature (or initial conditions) pre-determines whether the architecture of a system becomes similar; otherwise nurture influences whether a system becomes mixed, anti-ordered, or ordered. We propose the `Aryabhata formation scenario' to explain some planetary systems which host only water-rich worlds. We finish this paper with a discussion of future observational and theoretical works that may support or refute the results of this paper.

12 pages, 5 figures, accepted in A&A

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Cited by in corpus (9)

• A framework for the architecture of exoplanetary systems. I. Four classes of planetary system architecture
• Planetary Population Synthesis and the Emergence of Four Classes of Planetary System Architectures
• Unveiling the internal structure and formation history of the three planets transiting HIP 29442 (TOI-469) with CHEOPS
• Architecture Classification for Extrasolar Planetary Systems
• Earth-like planets hosting systems: Architecture and properties
• Diversities and similarities exhibited by multi-planetary systems and their architectures: I. Orbital spacings
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• The TESS-Keck Survey. XIX. A Warm Transiting Sub-Saturn Mass Planet and a non-Transiting Saturn Mass Planet Orbiting a Solar Analog
• On the Ordering of Exoplanet Systems