Characteristics of Kepler Planetary Candidates Based on the First Data Set: The Majority are Found to be Neptune-Size and Smaller

TL;DR

This paper analyzes the first data set from the Kepler Mission, revealing that most planetary candidates are Neptune-sized or smaller, with some multi-planet systems and near-resonant orbits.

Contribution

It provides the first characterization of Kepler planetary candidates, highlighting their size distribution and the presence of multi-planet systems.

Findings

Over half of the candidates are smaller than half Jupiter's radius.

Five potential multi-planet systems identified.

Presence of near-resonant period candidates.

Abstract

In the spring of 2009, the Kepler Mission commenced high-precision photometry on nearly 156,000 stars to determine the frequency and characteristics of small exoplanets, conduct a guest observer program, and obtain asteroseismic data on a wide variety of stars. On 15 June 2010 the Kepler Mission released data from the first quarter of observations. At the time of this publication, 706 stars from this first data set have exoplanet candidates with sizes from as small as that of the Earth to larger than that of Jupiter. Here we give the identity and characteristics of 306 released stars with planetary candidates. Data for the remaining 400 stars with planetary candidates will be released in February 2011. Over half the candidates on the released list have radii less than half that of Jupiter. The released stars include five possible multi-planet systems. One of these has two Neptune-size (2.3 and 2.5 Earth-radius) candidates with near-resonant periods.