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Chaotic Excitation and Tidal Damping in the GJ 876 System

Puranam, Abhijit and Batygin, Konstantin (2018) Chaotic Excitation and Tidal Damping in the GJ 876 System. Astronomical Journal, 155 (4). Art. No. 157. ISSN 1538-3881. doi:10.3847/1538-3881/aab09f.

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The M-dwarf GJ 876 is the closest known star to harbor a multi-planetary system. With three outer planets locked in a chaotic Laplace-type resonance and an appreciably eccentric short-period super-Earth, this system represents a unique exposition of extrasolar planetary dynamics. A key question that concerns the long-term evolution of this system, and the fate of close-in planets in general, is how the significant eccentricity of the inner-most planet is maintained against tidal circularization on timescales comparable to the age of the universe. Here, we employ stochastic secular perturbation theory and N-body simulations to show that the orbit of the inner-most planet is shaped by a delicate balance between extrinsic chaotic forcing and tidal dissipation. As such, the planet's orbital eccentricity represents an indirect measure of its tidal quality factor. Based on the system's present-day architecture, we estimate that the extrasolar super-Earth GJ 876 d has a tidal Q ~ 10^4–10^5, a value characteristic of solar system gas giants.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Batygin, Konstantin0000-0002-7094-7908
Additional Information:© 2018 The American Astronomical Society. Received 2017 October 24; revised 2018 February 13; accepted 2018 February 17; published 2018 March 20. We are grateful to Chris Spalding, Kat Deck, Elizabeth Bailey, Sarah Millholland, and Greg Laughlin for illuminating discussions, as well as to the anonymous referee for providing an insightful report. This research was supported by NSF grant AST1517936 and Caltech's Summer Undergraduate Research Fellowship (SURF) program.
Group:Astronomy Department
Funding AgencyGrant Number
Caltech Summer Undergraduate Research Fellowship (SURF)UNSPECIFIED
Subject Keywords:chaos – planetary systems – planets and satellites: dynamical evolution and stability
Issue or Number:4
Record Number:CaltechAUTHORS:20180327-125313666
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Official Citation:Abhijit Puranam and Konstantin Batygin 2018 AJ 155 157
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:85459
Deposited By: Tony Diaz
Deposited On:27 Mar 2018 20:30
Last Modified:15 Nov 2021 20:29

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