Seeking Distant Companions

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Science  06 May 2011:
Vol. 332, Issue 6030, pp. 641
DOI: 10.1126/science.332.6030.641-a

The Kepler satellite searches for planets around other stars by detecting the dimming of light that occurs when a planet passes in front of its star. Between 2 May and 16 September 2009, in its first 4 months of operation, Kepler looked at 156,453 stars in our galaxy, 1489 of which were considered of interest because their light curves—the graph of their brightness as a function of time—bore the signatures of planetary candidates. Testing for false positives, such as binary star systems, eliminated 492 stars, leaving 1235 planetary candidates around 997 stars: 827 in systems of single transiting planets and 408 in systems where more than one planet transits the same host star. Although not all the candidates have been confirmed through follow-up observations, the rate of false positives within the list of singles is thought to be 5 to 10% and that within multiples even lower. Latham et al. compared the properties of planet candidates in single and multiple systems. Systems with single transiting planets are more likely to include a planet larger than Neptune, suggesting that Jupiter-like planets in short-period orbits disrupt the orbital inclinations of smaller planets, making them less likely to preserve the flatness of the disk from which they originated and thus less likely to transit the star.

Astrophys. J. 732, L24 (2011).

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