Characteristics of Planetary Candidates Observed by Kepler. II. Analysis of the First Four Months of Data
Abstract
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 transitlike 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 Earthsize (R _{p} < 1.25 R _{⊕}), 288 superEarthsize (1.25 R _{⊕} <= R _{p} < 2 R _{⊕}), 662 Neptunesize (2 R _{⊕} <= R _{p} < 6 R _{⊕}), 165 Jupitersize (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 Earthsize 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 Earthsize 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 Earthsize candidates, 8% for superEarthsize candidates, 18% for Neptunesize candidates, 2% for Jupitersize candidates, and 0.1% for very large candidates; a total of 0.34 candidates per star. Multicandidate, transiting systems are frequent; 17% of the host stars have multicandidate systems, and 34% of all the candidates are part of multicandidate systems.
 Publication:

The Astrophysical Journal
 Pub Date:
 July 2011
 DOI:
 10.1088/0004637X/736/1/19
 arXiv:
 arXiv:1102.0541
 Bibcode:
 2011ApJ...736...19B
 Keywords:

 planetary systems;
 stars: statistics;
 planets and satellites: detection;
 surveys;
 Astrophysics  Earth and Planetary Astrophysics
 EPrint:
 106 pages, 15 figures, contains tables of candidates. Submitted to ApJ