Characteristics of planetary candidates observed by Kepler. II. Analysis of the first four months of data

William J. Borucki, David G. Koch, Gibor Basri, Natalie Batalha, Timothy M. Brown, Stephen T. Bryson, Douglas Caldwell, Jørgen Christensen-Dalsgaard, William D. Cochran, Edna DeVore, Edward W. Dunham, Thomas N. Gautier, John C. Geary, Ronald Gilliland, Alan Gould, Steve B. Howell, Jon M. Jenkins, David W. Latham, Jack J. Lissauer, Geoffrey W. MarcyJason Rowe, Dimitar Sasselov, Alan Boss, David Charbonneau, David Ciardi, Laurance Doyle, Andrea K. Dupree, Eric B. Ford, Jonathan Fortney, Matthew J. Holman, Sara Seager, Jason H. Steffen, Jill Tarter, William F. Welsh, Christopher Allen, Lars A. Buchhave, Jessie L. Christiansen, Bruce D. Clarke, Santanu Das, Jean Michel Désert, Michael Endl, Daniel Fabrycky, Francois Fressin, Michael Haas, Elliott Horch, Andrew Howard, Howard Isaacson, Hans Kjeldsen, Jeffery Kolodziejczak, Craig Kulesa, Jie Li, Philip W. Lucas, Pavel MacHalek, Donald McCarthy, Phillip MacQueen, Søren Meibom, Thibaut Miquel, Andrej Prsa, Samuel N. Quinn, Elisa V. Quintana, Darin Ragozzine, William Sherry, Avi Shporer, Peter Tenenbaum, Guillermo Torres, Joseph D. Twicken, Jeffrey Van Cleve, Lucianne Walkowicz, Fred C. Witteborn, Martin Still

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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 (Rp < 1.25 R), 288 super-Earth-size (1.25 R ≤ R p < 2 R), 662 Neptune-size (2 R ≤ Rp < 6 R), 165 Jupiter-size (6 R ≤ Rp < 15 R ), and 19 up to twice the size of Jupiter (15 R ≤ Rp < 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.

Original languageEnglish (US)
Article number19
JournalAstrophysical Journal
Issue number1
StatePublished - Jul 20 2011


  • planetary systems
  • planets and satellites: detection
  • stars: statistics
  • surveys

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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  • Kepler planetary candidates. II.

    Borucki, W. J. (Creator), Koch, D. G. (Creator), Basri, G. (Creator), Batalha, N. (Creator), Brown, T. M. (Creator), Bryson, S. T. (Creator), Caldwell, D. (Creator), Christensen-Dalsgaard, J. (Creator), Cochran, W. D. (Creator), DeVore, E. (Contributor), Dunham, E. W. (Creator), Gautier, T. N. (Creator), Geary, J. C. (Creator), Gilliland, R. (Creator), Gould, A. (Creator), Howell, S. B. (Creator), Jenkins, J. M. (Creator), Latham, D. W. (Creator), Lissauer, J. J. (Creator), Marcy, G. W. (Creator), Rowe, J. (Creator), Sasselov, D. (Creator), Boss, A. (Creator), Charbonneau, D. (Creator), Ciardi, D. (Creator), Doyle, L. (Creator), Dupree, A. K. (Creator), Ford, E. B. (Creator), Fortney, J. (Creator), Holman, M. J. (Creator), Seager, S. (Creator), Steffen, J. H. (Creator), Tarter, J. (Creator), Welsh, W. F. (Creator), Allen, C. (Creator), Buchhave, L. A. (Creator), Christiansen, J. L. (Creator), Clarke, B. D. (Creator), Das, S. (Creator), Désert, J. (Contributor), Endl, M. (Creator), Fabrycky, D. (Creator), Fressin, F. (Creator), Haas, M. (Creator), Horch, E. (Creator), Howard, A. (Creator), Isaacson, H. (Creator), Kjeldsen, H. (Creator), Kolodziejczak, J. (Creator), Kulesa, C. A. (Creator), Li, J. (Creator), Lucas, P. W. (Creator), MacHalek, P. (Contributor), McCarthy Jr, D. W. (Creator), MacQueen, P. (Creator), Meibom, S. (Creator), Miquel, T. (Creator), Prsa, A. (Creator), Quinn, S. N. (Creator), Quintana, E. V. (Creator), Ragozzine, D. (Creator), Sherry, W. (Creator), Shporer, A. (Creator), Tenenbaum, P. (Creator), Torres, G. (Creator), Twicken, J. D. (Creator), Van Cleve, J. (Creator), Walkowicz, L. (Creator), Witteborn, F. C. (Creator), Still, M. (Creator), Caldwell, D. (Creator), Gould, A. (Creator), Howell, S. B. (Creator), Jenkins, J. M. (Creator), Latham, D. W. (Creator), Charbonneau, D. (Creator), Ford, E. B. (Creator), Fortney, J. (Creator), Seager, S. (Creator), Welsh, W. F. (Creator), Christiansen, J. L. (Creator), Howard, A. (Creator), Kjeldsen, H. (Creator), Prsa, A. (Creator) & Quintana, E. V. (Creator), Centre de Donnees Strasbourg (CDS), 2012


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