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Architectures of Compact Super-Earth Systems Shaped by Instabilities

Goldberg, Max and Batygin, Konstantin (2022) Architectures of Compact Super-Earth Systems Shaped by Instabilities. Astronomical Journal, 163 (5). Art. No. 201. ISSN 0004-6256. doi:10.3847/1538-3881/ac5961.

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Compact nonresonant systems of sub-Jovian planets are the most common outcome of the planet formation process. Despite exhibiting broad overall diversity, these planets also display dramatic signatures of intrasystem uniformity in their masses, radii, and orbital spacings. Although the details of their formation and early evolution are poorly known, sub-Jovian planets are expected to emerge from their natal nebulae as multiresonant chains, owing to planet–disk interactions. Within the context of this scenario, the architectures of observed exoplanet systems can be broadly replicated if resonances are disrupted through postnebular dynamical instabilities. Here, we generate an ad hoc sample of resonant chains and use a suite of N-body simulations to show that instabilities can not only reproduce the observed period ratio distribution, but that the resulting collisions also modify the mass uniformity in a way that is consistent with the data. Furthermore, we demonstrate that primordial mass uniformity, motivated by the sample of resonant chains coupled with dynamical sculpting, naturally generates uniformity in orbital period spacing similar to what is observed. Finally, we find that almost all collisions lead to perfect mergers, but some form of postinstability damping is likely needed to fully account for the present-day dynamically cold architectures of sub-Jovian exoplanets.

Item Type:Article
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URLURL TypeDescription Paper ItemAbstract
Goldberg, Max0000-0003-3868-3663
Batygin, Konstantin0000-0002-7094-7908
Additional Information:© 2022. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Received 2021 August 23; revised 2022 February 18; accepted 2022 February 27; published 2022 April 8. We are thankful to Erik Petigura, Juliette Becker, Fred Adams, Andrew Howard, and Lauren Weiss for insightful discussions. We are especially grateful to the anonymous referee, whose input significantly improved this work. K.B. is grateful to Caltech, the Caltech Center for Comparative Planetary Evolution, the David and Lucile Packard Foundation, and the Alfred P. Sloan Foundation for their generous support.
Group:Caltech Center for Comparative Planetary Evolution
Funding AgencyGrant Number
Caltech Center for Comparative Planetary EvolutionUNSPECIFIED
David and Lucile Packard FoundationUNSPECIFIED
Alfred P. Sloan FoundationUNSPECIFIED
Subject Keywords:Exoplanet dynamics; Exoplanet astronomy; Orbital resonances; Exoplanet formation
Issue or Number:5
Classification Code:Unified Astronomy Thesaurus concepts: Exoplanet dynamics (490); Exoplanet astronomy (486); Orbital resonances (1181); Exoplanet formation (492)
Record Number:CaltechAUTHORS:20220414-26049000
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Official Citation:Max Goldberg and Konstantin Batygin 2022 AJ 163 201
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:114295
Deposited By: George Porter
Deposited On:19 Apr 2022 20:50
Last Modified:18 May 2022 22:37

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