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Dynamical orbital evolution scenarios of the wide-orbit eccentric planet HR 5183b

Mustill, Alexander J. and Davies, Melvyn B. and Blunt, Sarah and Howard, Andrew (2022) Dynamical orbital evolution scenarios of the wide-orbit eccentric planet HR 5183b. Monthly Notices of the Royal Astronomical Society, 509 (3). pp. 3616-3625. ISSN 0035-8711. doi:10.1093/mnras/stab3174.

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The recently discovered giant exoplanet HR5183b exists on a wide, highly eccentric orbit (a = 18 au, e = 0.84). Its host star possesses a common proper-motion companion which is likely on a bound orbit. In this paper, we explore scenarios for the excitation of the eccentricity of the planet in binary systems such as this, considering planet–planet scattering, Lidov–Kozai cycles from the binary acting on a single-planet system, or Lidov–Kozai cycles acting on a two-planet system that also undergoes scattering. Planet–planet scattering, in the absence of a binary companion, has a 2.8-7.2 per cent probability of pumping eccentricities to the observed values in our simulations, depending on the relative masses of the two planets. Lidov–Kozai cycles from the binary acting on an initially circular orbit can excite eccentricities to the observed value but require very specific orbital configurations for the binary and overall there is a low probability of catching the orbit at the high observed high eccentricity (0.6 per cent). The best case is provided by planet–planet scattering in the presence of a binary companion: here, the scattering provides the surviving planet with an initial eccentricity boost that is subsequently further increased by Kozai cycles from the binary. We find a success rate of 14.5 per cent for currently observing e ≥ 0.84 in this set-up. The single-planet plus binary and two-planet plus binary cases are potentially distinguishable if the mutual inclination of the binary and the planet can be measured, as the latter permits a broader range of mutual inclinations. The combination of scattering and Lidov–Kozai forcing may also be at work in other wide-orbit eccentric giant planets, which have a high rate of stellar binary companions.

Item Type:Article
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URLURL TypeDescription Paper
Mustill, Alexander J.0000-0002-2086-3642
Davies, Melvyn B.0000-0001-6080-1190
Blunt, Sarah0000-0002-3199-2888
Howard, Andrew0000-0001-8638-0320
Additional Information:© 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. Accepted 2021 October 28. Received 2021 September 27; in original form 2021 February 11. The authors thank Stephen Kane, Antoine Petit, and the anonymous referee for comments that improved the manuscript. AJM and MBD acknowledge support from project grant 2014.0017 ‘IMPACT’ from the Knut and Alice Wallenberg Foundation. AJM acknowledges support from Career grant 120/19C from the Swedish National Space Agency. The simulations were performed on resources provided by the Swedish National Infrastructure for Computing (SNIC) at Lunarc, partially funded by the Swedish Research Council through grant agreement no. 2016-07213. This research made use of ASTROPY,7 a community-developed core PYTHON package for Astronomy (Astropy Collaboration 2013, 2018). This research made use of NUMPY (Harris et al. 2020), SCIPY (Virtanen et al. 2020), and MATPLOTLIB (Hunter 2007). This work has made use of data from the European Space Agency (ESA) mission Gaia (, processed by the Gaia Data Processing and Analysis Consortium (DPAC, Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. DATA AVAILABILITY STATEMENT. The data underlying this paper will be made available on reasonable request to the corresponding author.
Group:Astronomy Department
Funding AgencyGrant Number
Knut and Alice Wallenberg Foundation2014.0017
Swedish National Space Agency120/19C
Swedish Research Council2016-07213
Gaia Multilateral AgreementUNSPECIFIED
NSF Graduate Research FellowshipUNSPECIFIED
Subject Keywords:planets and satellites: dynamical evolution and stability, planets and satellites: formation, binaries: general, stars: individual: HR5183
Issue or Number:3
Record Number:CaltechAUTHORS:20220309-966443000
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Official Citation:Alexander J Mustill, Melvyn B Davies, Sarah Blunt, Andrew Howard, Dynamical orbital evolution scenarios of the wide-orbit eccentric planet HR 5183b, Monthly Notices of the Royal Astronomical Society, Volume 509, Issue 3, January 2022, Pages 3616–3625,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:113848
Deposited By: George Porter
Deposited On:11 Mar 2022 15:37
Last Modified:11 Mar 2022 15:37

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