The findings increase the number of planet candidates identified by Kepler to-date to 1,235. Of these, 68 are approximately Earth-size; 288 are super-Earth-size; 662 are Neptune-size; 165 are the size of Jupiter and 19 are larger than Jupiter. Of the 54 new planet candidates found in the habitable zone, five are near Earth-sized. The remaining 49 habitable zone candidates range from super-Earth size -- up to twice the size of Earth -- to larger than Jupiter. The findings are based on the results of observations conducted May 12 to Sept. 17, 2009 of more than 156,000 stars in Kepler’s field of view, which covers approximately 1/400 of the sky.
NASA Finds Earth-size Planet Candidates in the Habitable Zone | NASA
15万6千の星を観測して、1235の惑星を発見し、うち5つは地球サイズでハビタブルゾーンにあるということらしい。
Thus, approximately 0.011 x 0.866 = 1% of the solar-like stars with planets should show Earth-size transits.
Kepler & K2 Science Center
によると、地球サイズの惑星があったとしてそれがケプラーで検出できる確率は約１％。
合わせると、15万6千のうち約500に地球っぽい惑星があるということになる。つまり300分の１。なんか、思ったより大きい数字だ。
