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Friends of Hot Jupiters. IV. Stellar companions beyond 50 AU might facilitate giant planet formation, but most are unlikely to cause Kozai-Lidov migration

Ngo, Henry and Knutson, Heather A. and Hinkley, Sasha and Bryan, Marta and Crepp, Justin R. and Batygin, Konstantin and Crossfield, Ian and Hansen, Brad and Howard, Andrew W. and Johnson, John A. and Mawet, Dimitri and Morton, Timothy D. and Muirhead, Philip S. and Wang, Ji (2016) Friends of Hot Jupiters. IV. Stellar companions beyond 50 AU might facilitate giant planet formation, but most are unlikely to cause Kozai-Lidov migration. Astrophysical Journal, 827 (1). Art. No. 8. ISSN 0004-637X. http://resolver.caltech.edu/CaltechAUTHORS:20160707-153537679

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Abstract

Stellar companions can influence the formation and evolution of planetary systems, but there are currently few observational constraints on the properties of planet-hosting binary star systems. We search for stellar companions around 77 transiting hot Jupiter systems to explore the statistical properties of this population of companions as compared to field stars of similar spectral type. After correcting for survey incompleteness, we find that 47% ± 7% of hot Jupiter systems have stellar companions with semimajor axes between 50 and 2000 au. This is 2.9 times larger than the field star companion fraction in this separation range, with a significance of 4.4σ. In the 1–50 au range, only 3.9^(+4.5)_(-2.0)% of hot Jupiters host stellar companions, compared to the field star value of 16.4% ± 0.7%, which is a 2.7σ difference. We find that the distribution of mass ratios for stellar companions to hot Jupiter systems peaks at small values and therefore differs from that of field star binaries which tend to be uniformly distributed across all mass ratios. We conclude that either wide separation stellar binaries are more favorable sites for gas giant planet formation at all separations, or that the presence of stellar companions preferentially causes the inward migration of gas giant planets that formed farther out in the disk via dynamical processes such as Kozai–Lidov oscillations. We determine that less than 20% of hot Jupiters have stellar companions capable of inducing Kozai–Lidov oscillations assuming initial semimajor axes between 1 and 5 au, implying that the enhanced companion occurrence is likely correlated with environments where gas giants can form efficiently.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.3847/0004-637X/827/1/8DOIArticle
http://iopscience.iop.org/article/10.3847/0004-637X/827/1/8/metaPublisherArticle
http://arxiv.org/abs/1606.07102arXivDiscussion Paper
ORCID:
AuthorORCID
Ngo, Henry0000-0001-5172-4859
Knutson, Heather A.0000-0002-0822-3095
Hinkley, Sasha0000-0001-8074-2562
Bryan, Marta0000-0002-6076-5967
Howard, Andrew W.0000-0001-8638-0320
Mawet, Dimitri0000-0002-8895-4735
Morton, Timothy D.0000-0002-8537-5711
Muirhead, Philip S.0000-0002-0638-8822
Additional Information:© 2016 The American Astronomical Society. Received 2016 May 16; revised 2016 June 16; accepted 2016 June 17; published 2016 August 3. This work was supported by NASA grant NNX14AD24G. H.N. is grateful for funding support from the Natural Sciences and Engineering Research Council of Canada and the NASA Earth and Space Science Fellowship Program grant NNX15AR12H. This work was based on observations at the W. M. Keck Observatory granted by the California Institute of Technology. We thank the observers who contributed to the measurements reported here and acknowledge the efforts of the Keck Observatory staff. We extend special thanks to those of Hawaiian ancestry on whose sacred mountain of Mauna Kea we are privileged to be guests. Facility: Keck:II (NIRC2) - KECK II Telescope.
Funders:
Funding AgencyGrant Number
NASANNX14AD24G
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
NASA Earth and Space Science FellowshipNNX15AR12H
Subject Keywords:binaries: close – binaries: eclipsing – methods: observational – planetary systems – planets and satellites: dynamical evolution and stability – techniques: high angular resolution
Record Number:CaltechAUTHORS:20160707-153537679
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20160707-153537679
Official Citation:Henry Ngo et al 2016 ApJ 827 8
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:68897
Collection:CaltechAUTHORS
Deposited By: Joy Painter
Deposited On:08 Jul 2016 02:08
Last Modified:12 Oct 2017 22:14

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