Assessing the Effect of Stellar Companions from Highresolution Imaging of Kepler Objects of Interest
Abstract
We report on 176 close (<2″) stellar companions detected with highresolution imaging near 170 hosts of Kepler Objects of Interest (KOIs). These Kepler targets were prioritized for imaging followup based on the presence of small planets, so most of the KOIs in these systems (176 out of 204) have nominal radii <6 {R}_{\oplus }. Each KOI in our sample was observed in at least two filters with adaptive optics, speckle imaging, lucky imaging, or the Hubble Space Telescope. Multifilter 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 highresolution imaging or spectroscopy.
 Publication:

The Astronomical Journal
 Pub Date:
 March 2017
 DOI:
 10.3847/15383881/153/3/117
 arXiv:
 arXiv:1701.06577
 Bibcode:
 2017AJ....153..117H
 Keywords:

 binaries: visual;
 planets and satellites: detection;
 planets and satellites: fundamental parameters;
 techniques: high angular resolution;
 techniques: photometric;
 Astrophysics  Earth and Planetary Astrophysics
 EPrint:
 23 pages, 12 figures. Accepted for publication in The Astronomical Journal