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High-Contrast Imaging of Intermediate-Mass Giants with Long-Term Radial Velocity Trends
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Number of Authors: 65
2016 (English)In: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 825, no 2, 127Article in journal (Refereed) Published
Abstract [en]

A radial velocity (RV) survey for intermediate-mass giants has been in operation for over a decade at Okayama Astrophysical Observatory (OAO). The OAO survey has revealed that some giants show long-term linear RV accelerations (RV trends), indicating the presence of outer companions. Direct-imaging observations can help clarify what objects generate these RV trends. We present the results of high-contrast imaging observations of six intermediate-mass giants with long-term RV trends using the Subaru Telescope and HiCIAO camera. We detected co-moving companions to gamma Hya B (0.61(-0.14)(+0.12)M(circle dot)), HD 5608 B (0.10 +/- 0.01M(circle dot)), and HD 109272 B (0.28 +/- 0.06M(circle dot)). For the remaining targets (iota Dra, 18 Del, and HD 14067), we exclude companions more massive than 30-60 M-Jup at projected separations of 1 ''-7 ''. We examine whether these directly imaged companions or unidentified long-period companions can account for the RV trends observed around the six giants. We find that the Kozai mechanism can explain the high eccentricity of the inner planets iota Dra b, HD 5608 b, and HD 14067 b.

Place, publisher, year, edition, pages
2016. Vol. 825, no 2, 127
Keyword [en]
binaries: general, methods: observational, planetary systems, techniques: high angular resolution, techniques: radial velocities
National Category
Astronomy, Astrophysics and Cosmology
URN: urn:nbn:se:su:diva-134295DOI: 10.3847/0004-637X/825/2/127ISI: 000381940800045OAI: diva2:1025303
Available from: 2016-10-04 Created: 2016-10-03 Last updated: 2016-10-04Bibliographically approved

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Janson, Markus
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