Understanding the Effects of Stellar Multiplicity on the Derived Planet Radii from Transit Surveys: Implications for Kepler, K2, and TESS
Abstract
We present a study on the effect of undetected stellar companions on the derived planetary radii for Kepler Objects of Interest (KOIs). The current production of the KOI list assumes that each KOI is a single star. Not accounting for stellar multiplicity statistically biases the planets toward smaller radii. The bias toward smaller radii depends on the properties of the companion stars and whether the planets orbit the primary or the companion stars. Defining a planetary radius correction factor, X_R, we find that if the KOIs are assumed to be single, then, on average, the planetary radii may be underestimated by a factor of 〈X_R〉 ≈ 1.5. If typical radial velocity and high-resolution imaging observations are performed and no companions are detected, then this factor reduces to 〈X_R〉 ≈ 1.2. The correction factor 〈X_R〉 is dependent on the primary star properties and ranges from 〈X_R〉 ≈ 1.6 for A and F stars to 〈X_R〉 ≈ 1.2 for K and M stars. For missions like K2 and TESS where the stars may be closer than the stars in the Kepler target sample, observational vetting (primary imaging) reduces the radius correction factor to 〈X_R〉 ≈ 1.1. Finally, we show that if the stellar multiplicity rates are not accounted for correctly, then occurrence rate calculations for Earth-sized planets may overestimate the frequency of small planets by as much as 15%–20%.
Additional Information
© 2015 The American Astronomical Society. Received 2015 January 19; accepted 2015 March 11; published 2015 May 14. The authors thank Ji Wang, Tim Morton, and Gerard van Belle for useful discussions during the writing of this paper. This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. Portions of this work were performed at the California Institute of Technology under contract with the National Aeronautics and Space Administration.Attached Files
Published - 0004-637X_805_1_16.pdf
Submitted - 1503.03516v1.pdf
Erratum - Ciardi_2017_ApJ_834_96.pdf
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- Eprint ID
- 58368
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- CaltechAUTHORS:20150619-090724636
- NASA/Caltech
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2015-06-20Created from EPrint's datestamp field
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2021-11-10Created from EPrint's last_modified field
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- Infrared Processing and Analysis Center (IPAC)