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Characteristics of Planetary Candidates Observed by Kepler. II. Analysis of the First Four Months of Data

Borucki, William J. and Ciardi, David and Howard, Andrew (2011) Characteristics of Planetary Candidates Observed by Kepler. II. Analysis of the First Four Months of Data. Astrophysical Journal, 736 (1). Art. No. 19. ISSN 0004-637X.

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On 2011 February 1 the Kepler mission released data for 156,453 stars observed from the beginning of the science observations on 2009 May 2 through September 16. There are 1235 planetary candidates with transit-like signatures detected in this period. These are associated with 997 host stars. Distributions of the characteristics of the planetary candidates are separated into five class sizes: 68 candidates of approximately Earth-size (R_p < 1.25 R_⊕), 288 super-Earth-size (1.25 R_⊕ ≤ R_p < 2 R_⊕), 662 Neptune-size (2 R_⊕ ≤ R_p < 6 R_⊕), 165 Jupiter-size (6 R_⊕ ≤ R_p < 15 R_⊕), and 19 up to twice the size of Jupiter (15 R_⊕ ≤ R_p < 22 R_⊕). In the temperature range appropriate for the habitable zone, 54 candidates are found with sizes ranging from Earth-size to larger than that of Jupiter. Six are less than twice the size of the Earth. Over 74% of the planetary candidates are smaller than Neptune. The observed number versus size distribution of planetary candidates increases to a peak at two to three times the Earth-size and then declines inversely proportional to the area of the candidate. Our current best estimates of the intrinsic frequencies of planetary candidates, after correcting for geometric and sensitivity biases, are 5% for Earth-size candidates, 8% for super-Earth-size candidates, 18% for Neptune-size candidates, 2% for Jupiter-size candidates, and 0.1% for very large candidates; a total of 0.34 candidates per star. Multi-candidate, transiting systems are frequent; 17% of the host stars have multi-candidate systems, and 34% of all the candidates are part of multi-candidate systems.

Item Type:Article
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URLURL TypeDescription
Ciardi, David0000-0002-5741-3047
Howard, Andrew0000-0001-8638-0320
Additional Information:© 2011 American Astronomical Society. Received 2011 January 3; accepted 2011 March 10; published 2011 June 29. Kepler was competitively selected as the tenth Discovery mission. Funding for this mission is provided by NASA’s Science Mission Directorate. Some of the data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Keck Observatory was made possible by the generous financial support of the W. M. Keck Foundation. We sincerely thank Andrew Gould for his timely, thorough, and very helpful review of this paper. The authors thank many people who gave so generously of their time to make this mission a success.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
W. M. Keck FoundationUNSPECIFIED
Subject Keywords:planetary systems; stars: statistics; planets and satellites: detection; surveys
Issue or Number:1
Classification Code:PACS: 97.82.-j; 95.10.Gi
Record Number:CaltechAUTHORS:20110801-102705206
Persistent URL:
Official Citation:Characteristics of Planetary Candidates Observed by Kepler. II. Analysis of the First Four Months of Data William J. Borucki et al. 2011 ApJ 736 19
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:24610
Deposited By: Ruth Sustaita
Deposited On:01 Aug 2011 18:28
Last Modified:03 Oct 2019 02:58

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