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Dynamics of Planetary Systems within Star Clusters: Aspects of the Solar System’s Early Evolution

Batygin, Konstantin and Adams, Fred C. and Batygin, Yuri K. and Petigura, Erik A. (2020) Dynamics of Planetary Systems within Star Clusters: Aspects of the Solar System’s Early Evolution. Astronomical Journal, 159 (3). Art. No. 101. ISSN 1538-3881. doi:10.3847/1538-3881/ab665d.

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Most planetary systems—including our own—are born within stellar clusters, where interactions with neighboring stars can help shape the system architecture. This paper develops an orbit-averaged formalism to characterize the cluster's mean-field effects, as well as the physics of long-period stellar encounters. Our secular approach allows for an analytic description of the dynamical consequences of the cluster environment on its constituent planetary systems. We analyze special cases of the resulting Hamiltonian, corresponding to eccentricity evolution driven by planar encounters, as well as hyperbolic perturbations upon dissipative disks. We subsequently apply our results to the early evolution of our solar system, where the cluster's collective potential perturbs the solar system's plane, and stellar encounters act to increase the velocity dispersion of the Kuiper Belt. Our results are twofold. First, we find that cluster effects can alter the mean plane of the solar system by ≾1° and are thus insufficient to explain the ψ ≈ 6° obliquity of the Sun. Second, we delineate the extent to which stellar flybys excite the orbital dispersion of the cold classical Kuiper Belt and show that while stellar flybys may grow the cold belt's inclination by the observed amount, the resulting distribution is incompatible with the data. Correspondingly, our calculations place an upper limit on the product of the stellar number density and residence time of the Sun in its birth cluster, η τ ≾ 2 × 10⁴ Myr pc⁻³.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Batygin, Konstantin0000-0002-7094-7908
Adams, Fred C.0000-0002-8167-1767
Batygin, Yuri K.0000-0001-9422-6112
Petigura, Erik A.0000-0003-0967-2893
Additional Information:© 2020 The American Astronomical Society. Received 2019 September 1; revised 2019 November 26; accepted 2019 December 29; published 2020 February 12. We are thankful to Mike Brown, Alessandro Morbidelli, Greg Laughlin, Gongjie Li, and Dimitri Veras for insightful discussions. We thank the anonymous referee for a careful review of the manuscript. K.B. is grateful to the David and Lucile Packard Foundation and the Alfred P. Sloan Foundation for their generous support.
Group:Astronomy Department
Funding AgencyGrant Number
David and Lucile Packard FoundationUNSPECIFIED
Alfred P. Sloan FoundationUNSPECIFIED
Subject Keywords:Celestial mechanics; Kuiper belt; Young star clusters
Issue or Number:3
Classification Code:Unified Astronomy Thesaurus concepts: Celestial mechanics (211); Kuiper belt (893); Young star clusters (1833)
Record Number:CaltechAUTHORS:20200212-101042017
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Official Citation:Konstantin Batygin et al 2020 AJ 159 101
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:101237
Deposited By: Tony Diaz
Deposited On:12 Feb 2020 18:23
Last Modified:16 Nov 2021 18:00

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