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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
Knutson, Heather A.
Crepp, Justin R.
Howard, Andrew W.
Johnson, John A.
Morton, Timothy D.
Muirhead, Philip S.
AffiliationUniv Arizona, Lunar & Planetary Lab
planets and satellites: dynamical evolution and stability
techniques: high angular resolution
MetadataShow full item record
PublisherIOP PUBLISHING LTD
CitationFRIENDS OF HOT JUPITERS. IV. STELLAR COMPANIONS BEYOND 50 au MIGHT FACILITATE GIANT PLANET FORMATION, BUT MOST ARE UNLIKELY TO CAUSE KOZAI–LIDOV MIGRATION 2016, 827 (1):8 The Astrophysical Journal
JournalThe Astrophysical Journal
Rights© 2016. The American Astronomical Society. All rights reserved.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at email@example.com.
AbstractStellar 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 4.4 sigma. In the 1-50 au range, only 3.9(-2.0)(+4.5)% of hot Jupiters host stellar companions, compared to the field star value of 16.4% +/- 0.7%, which is a 2.7 sigma 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.
VersionFinal published version
SponsorsNASA [NNX14AD24G]; Natural Sciences and Engineering Research Council of Canada; NASA Earth and Space Science Fellowship Program [NNX15AR12H]; California Institute of Technology