/sci/ - Science & Math

>The period and radius of Kepler planets in the sample, around bright stars,
are plotted. The lower right corner is relatively empty, probably owing to low SNR there, not because small planets are absent from long periods. The upper left corner is relatively sparse, in spite of an expected high SNR there, implying a deficit of large planets on short-period orbits. The left side of the diagram is relatively empty owing to an apparent paucity of planets of all sizes at periods less than 3 days. The right side of the diagram is not completely sampled in the current database, so should be ignored here.

>In the current Kepler database (B2011), transits with periods less than 42 days for bright, “Sun-like” FGK target stars are analyzed in order to estimate the frequency of terrestrial, habitable-zone planets in the target population, giving ⊕ ≃ (34 ± 14)%. The quoted uncertainty is the formal error in projecting the numbers of short-period planets. The true uncertainty will remain unknown until Kepler observations of orbital periods in the 1000-day range become available.