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Exterior Companions to Hot Jupiters Orbiting Cool Stars Are Coplanar

Becker, Juliette C. and Vanderburg, Andrew and Adams, Fred C. and Khain, Tali and Bryan, Marta (2017) Exterior Companions to Hot Jupiters Orbiting Cool Stars Are Coplanar. Astronomical Journal, 154 (6). Art. No. 230. ISSN 1538-3881. doi:10.3847/1538-3881/aa9176.

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The existence of hot Jupiters has challenged theories of planetary formation since the first extrasolar planets were detected. Giant planets are generally believed to form far from their host stars, where volatile materials like water exist in their solid phase, making it easier for giant planet cores to accumulate. Several mechanisms have been proposed to explain how giant planets can migrate inward from their birth sites to short-period orbits. One such mechanism, called Kozai–Lidov migration, requires the presence of distant companions in orbits inclined by more than ~40° with respect to the plane of the hot Jupiter's orbit. The high occurrence rate of wide companions in hot-Jupiter systems lends support to this theory for migration. However, the exact orbital inclinations of these detected planetary and stellar companions is not known, so it is not clear whether the mutual inclination of these companions is large enough for the Kozai–Lidov process to operate. This paper shows that in systems orbiting cool stars with convective outer layers, the orbits of most wide planetary companions to hot Jupiters must be well aligned with the orbits of the hot Jupiters and the spins of the host stars. For a variety of possible distributions for the inclination of the companion, the width of the distribution must be less than ~20° to recreate the observations with good fidelity. As a result, the companion orbits are likely well aligned with those of the hot Jupiters, and the Kozai–Lidov mechanism does not enforce migration in these systems.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Becker, Juliette C.0000-0002-7733-4522
Vanderburg, Andrew0000-0001-7246-5438
Adams, Fred C.0000-0002-8167-1767
Khain, Tali0000-0001-7721-6457
Bryan, Marta0000-0002-6076-5967
Additional Information:© 2017 The American Astronomical Society. Received 2017 August 19; revised 2017 October 2; accepted 2017 October 3; published 2017 November 16. We thank Gongjie Li, Heather Knutson, Josh Winn, Ben Montet, Danielle Piskorz, Sarah Millholland, Clara Eng, and Iryna Butsky for useful conversations. We also thank Michael Dieterle for visualization suggestions, and thank the referee, Chris Spalding, for prompt and useful feedback. J.C.B. and A.V. are supported by the NSF Graduate Research Fellowship grant Nos. DGE 1256260 and 1144152, respectively. This work was performed in part under contract with the California Institute of Technology (Caltech)/Jet Propulsion Laboratory (JPL) funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute. This work used both the Extreme Science and Engineering Discovery Environment (XSEDE; NSF grant number ACI-1053575) and resources provided by the Open Science Grid, which is supported by the National Science Foundation and the U.S. Department of Energy's Office of Science.
Funding AgencyGrant Number
NSF Graduate Research FellowshipDGE-1256260
NSF Graduate Research FellowshipDGE-1144152
Department of Energy (DOE)UNSPECIFIED
Subject Keywords:planets and satellites: dynamical evolution and stability – planets and satellites: gaseous planets
Issue or Number:6
Record Number:CaltechAUTHORS:20171130-095341167
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Official Citation:Juliette C. Becker et al 2017 AJ 154 230
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:83591
Deposited By: Tony Diaz
Deposited On:30 Nov 2017 18:09
Last Modified:15 Nov 2021 20:12

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