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Investigation of Kepler Objects of Interest Stellar Parameters from Observed Transit Durations

Plavchan, Peter and Bilinski, Christopher and Currie, Thayne (2014) Investigation of Kepler Objects of Interest Stellar Parameters from Observed Transit Durations. Publications of the Astronomical Society of the Pacific, 126 (935). pp. 34-47. ISSN 0004-6280.

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The Kepler mission discovery of candidate transiting exoplanets (KOIs) enables a plethora of ensemble analyses of the architecture and properties of exoplanetary systems. We compare the observed transit durations of KOIs to a synthetic distribution generated from the known eccentricities of radial velocity (RV) discovered exoplanets. We find that the Kepler and RV distributions differ at a statistically significant level. We identify three related systematic trends that are likely due to errors in stellar radii, which in turn affect the inferred exoplanet radii and the distribution thereof, and prevent a valid analysis of the underlying ensemble eccentricity distribution. First, 15% of KOIs have transit durations >20% longer than the transit duration expected for an edge-on circular orbit, including 92 KOIs with transit durations >50% longer, when only a handful of such systems are expected. Second, the median transit duration is too long by up to ∼25%. Random errors of < 50% in the stellar radius are not adequate to account for these two trends. We identify that incorrect estimates of stellar metallicity and extinction could account for these anomalies, rather than astrophysical effects such as eccentric exoplanets improbably transiting near apastron. Third, we find that the median transit duration is correlated with stellar radius, when no such trend is expected. All three effects are still present, although less pronounced, when considering only multiple transiting KOI systems which are thought to have a low false-positive rate. Improved stellar parameters for KOIs are necessary for the validity of future ensemble tests of exoplanetary systems found by Kepler.

Item Type:Article
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URLURL TypeDescription
Plavchan, Peter0000-0002-8864-1667
Currie, Thayne0000-0002-7405-3119
Additional Information:© 2014 Astronomical Society of the Pacific. Received 2013 March 18; accepted 2013 November 11; published 2013 December 19. We thank the anonymous referee for their constructive input on improving the clarity, presentation and content 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.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Subject Keywords:Extrasolar planets
Issue or Number:935
Record Number:CaltechAUTHORS:20140314-113503792
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Official Citation:Investigation of Kepler Objects of Interest Stellar Parameters from Observed Transit Durations Peter Plavchan, Christopher Bilinski, and Thayne Currie Publications of the Astronomical Society of the Pacific , Vol. 126, No. 935 (January 2014), pp. 34-47 Published by: The University of Chicago Press on behalf of the Astronomical Society of the Pacific Article DOI: 10.1086/674819 Article Stable URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:44316
Deposited By: Ruth Sustaita
Deposited On:14 Mar 2014 21:00
Last Modified:09 Mar 2020 13:18

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