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Is there an exoplanet in the Solar System?

Alexander J., Mustill Sean N. Raymond 1 Melvyn B., Davies 2
1 ECLIPSE 2016
LAB - Laboratoire d'Astrophysique de Bordeaux [Pessac]
Abstract : We investigate the prospects for the capture of the proposed Planet 9 from other stars in the Sun's birth cluster. Any capture scenario must satisfy three conditions: the encounter must be more distant than ~150 au to avoid perturbing the Kuiper belt; the other star must have a wide-orbit planet (a>~100au); the planet must be captured onto an appropriate orbit to sculpt the orbital distribution of wide-orbit Solar System bodies. Here we use N-body simulations to show that these criteria may be simultaneously satisfied. In a few percent of slow close encounters in a cluster, bodies are captured onto heliocentric, Planet 9-like orbits. During the ~100 Myr cluster phase, many stars are likely to host planets on highly-eccentric orbits with apastron distances beyond 100 au if Neptune-sized planets are common and susceptible to planet--planet scattering. While the existence of Planet 9 remains unproven, we consider capture from one of the Sun's young brethren a plausible route to explain such an object's orbit. Capture appears to predict a large population of Trans-Neptunian Objects (TNOs) whose orbits are aligned with the captured planet, and we propose that different formation mechanisms will be distinguishable based on their imprint on the distribution of TNOs.
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Contributor : Marie-Paule Pomies <>
Submitted on : Friday, March 25, 2016 - 9:29:56 AM
Last modification on : Friday, April 5, 2019 - 8:24:00 PM

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Alexander J., Mustill, Sean N. Raymond, Melvyn B., Davies. Is there an exoplanet in the Solar System?. Monthly Notices of the Royal Astronomical Society: Letters, Oxford Journals, 2016, 460 (1), pp.L109-L113 ⟨10.1093/mnrasl/slw075⟩. ⟨hal-01293594⟩



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