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Assessing the Effect of Stellar Companions from High-resolution Imaging of Kepler Objects of Interest

Hirsch, Lea A. and Ciardi, David R. and Howard, Andrew W. and Everett, Mark E. and Furlan, Elise and Saylors, Mindy and Horch, Elliott P. and Howell, Steve B. and Teske, Johanna and Marcy, Geoffrey W. (2017) Assessing the Effect of Stellar Companions from High-resolution Imaging of Kepler Objects of Interest. Astronomical Journal, 153 (3). Art. No. 117. ISSN 0004-6256.

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We report on 176 close (<2'') stellar companions detected with high-resolution imaging near 170 hosts of Kepler Objects of Interest (KOIs). These Kepler targets were prioritized for imaging follow-up based on the presence of small planets, so most of the KOIs in these systems (176 out of 204) have nominal radii <6 R⊕. Each KOI in our sample was observed in at least two filters with adaptive optics, speckle imaging, lucky imaging, or the Hubble Space Telescope. Multi-filter photometry provides color information on the companions, allowing us to constrain their stellar properties and assess the probability that the companions are physically bound. We find that 60%–80% of companions within 1'' are bound, and the bound fraction is >90% for companions within 0.”5; the bound fraction decreases with increasing angular separation. This picture is consistent with simulations of the binary and background stellar populations in the Kepler field. We also reassess the planet radii in these systems, converting the observed differential magnitudes to a contamination in the Kepler bandpass and calculating the planet radius correction factor, X_R = R_p (true)/R_p (single). Under the assumption that planets in bound binaries are equally likely to orbit the primary or secondary, we find a mean radius correction factor for planets in stellar multiples of X_R = 1.65. If stellar multiplicity in the Kepler field is similar to the solar neighborhood, then nearly half of all Kepler planets may have radii underestimated by an average of 65%, unless vetted using high-resolution imaging or spectroscopy.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Hirsch, Lea A.0000-0001-8058-7443
Ciardi, David R.0000-0002-5741-3047
Howard, Andrew W.0000-0001-8638-0320
Everett, Mark E.0000-0002-0885-7215
Furlan, Elise0000-0001-9800-6248
Horch, Elliott P.0000-0003-2159-1463
Howell, Steve B.0000-0002-2532-2853
Marcy, Geoffrey W.0000-0002-2909-0113
Additional Information:© 2017 The American Astronomical Society. Received 2016 July 5; revised 2016 November 29; accepted 2017 January 13; published 2017 February 20. We thank the anonymous referee for a thorough and detailed report and many helpful suggestions and comments. This project was begun during and partially funded by the Infrared Processing and Analysis Center's Visiting Graduate Student Fellowship at the California Institute of Technology. The authors would like to thank James Graham for useful discussions while working on this project. This research has made use of the NASA Exoplanet Archive and ExoFOP, which are operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. Software: Dartmouth Stellar Evolution models (Dotter et al. 2008), TRILEGAL (Girardi et al. 2005).
Group:Infrared Processing and Analysis Center (IPAC), Astronomy Department
Funding AgencyGrant Number
Subject Keywords:binaries: visual – planets and satellites: detection – planets and satellites: fundamental parameters – techniques: high angular resolution – techniques: photometric
Issue or Number:3
Record Number:CaltechAUTHORS:20170224-134350419
Persistent URL:
Official Citation:Lea A. Hirsch et al 2017 AJ 153 117
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:74527
Deposited By: Tony Diaz
Deposited On:24 Feb 2017 22:10
Last Modified:03 Oct 2019 16:39

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