TERRESTRIAL PLANET OCCURRENCE RATES FOR THEKEPLERGK DWARF SAMPLE

Abstract

We measure planet occurrence rates using the planet candidates discovered by the Q1-Q16 Kepler pipeline search. This study examines planet occurrence rates for the Kepler GK dwarf target sample for planet radii, 0.75≤R p ≤2.5 R ⊕ , and orbital periods, 50≤P orb ≤300 days, with an emphasis on a thorough exploration and identification of the most important sources of systematic uncertainties. Integrating over this parameter space, we measure an occurrence rate of F 0 =0.77 planets per star, with an allowed range of 0.3≤ F 0 ≤1.9. The allowed range takes into account both statistical and systematic uncertainties, and values of F 0 beyond the allowed range are significantly in disagreement with our analysis. We generally find higher planet occurrence rates and a steeper increase in planet occurrence rates towards small planets than previous studies of the Kepler GK dwarf sample. Through extrapolation, we find that the one year orbital period terrestrial planet occurrence rate, ζ 1.0 =0.1, with an allowed range of 0.01≤ ζ 1.0 ≤2, where ζ 1.0 is defined as the number of planets per star within 20% of the R p and P orb of Earth. For G dwarf hosts, the ζ 1.0 parameter space is a subset of the larger η ⊕ parameter space, thus ζ 1.0 places a lower limit on η ⊕ for G dwarf hosts. From our analysis, we identify the leading sources of systematics impacting Kepler occurrence rate determinations as: reliability of the planet candidate sample, planet radii, pipeline completeness, and stellar parameters.

The California-Kepler Survey. I. High-resolution Spectroscopy of 1305 Stars Hosting Kepler Transiting Planets*

“…Many studies quantified the occurrence of planets as a function of planet radius and orbital period (Howard et al 2012;Dressing & Charbonneau 2013;Fressin et al 2013;Petigura et al 2013b). Further work showed that Earth-size planets are common in and near the habitable zone (Petigura et al 2013a;Burke et al 2015;Dressing & Charbonneau 2015).…”

The Anglo-Australian Planet Search Xxiv: The Frequency of Jupiter Analogs

“…This is due in large part to the flood of data from the Kepler spacecraft mission, which has provided evidence that small planets are exceedingly common (e.g., Dressing & Charbonneau 2015;Fressin et al 2013;Burke et al 2015). These findings are a critical step toward answering the fundamental question "how common are planetary systems like our own solar system?"…”

Precise Masses in the WASP-47 System

“…After the second of the Kepler space telescope's four reaction wheels failed and the spacecraft was repurposed to undertake the K2 mission (Howell et al 2014), the parade of stunning results from the original Kepler mission-from low-density multitransiting systems (Lissauer et al 2011), to evaporating and disintegrating sub-Mercury-sized planets (Rappaport et al 2012), to an abundance of small, likely rocky planets in their host stars' habitable zones (Dressing & Charbonneau 2013;Petigura et al 2013a;Burke et al 2015)-was largely expected to slow. The Kepler era of discovery was instead expected to give way to a new era in which the K2 mission would largely find more of the same kinds of planets that had been previously discovered, just orbiting brighter stars or in different environments.…”