PLANET OCCURRENCE WITHIN 0.25 AU OF SOLAR-TYPE STARS FROM KEPLER

By Andrew W. Howard, G. Marcy, S. Bryson, Jon M. Jenkins, J. Rowe, N. Batalha, William J. Borucki, D. Koch, E. Dunham, T. Gautier and 52 more. 2011

943 citations recorded by the source corpus.

We report the distribution of planets as a function of planet radius, orbital period, and stellar effective temperature for orbital periods less than 50 days around solar-type (GK) stars. These results are based on the 1235 planets (formally “planet candidates”) from the Kepler mission that include a nearly complete set of detected planets as small as 2 R⊕. For each of the 156,000 target stars, we assess the detectability of planets as a function of planet radius, Rp, and orbital period, P, using a measure of the detection efficiency for each star. We also correct for the geometric probability of transit, R⋆/a. We consider first Kepler target stars within the “solar subset” having Teff = 4100–6100 K, log g = 4.0–4.9, and Kepler magnitude Kp < 15 mag, i.e., bright, main-sequence GK stars. We include only those stars having photometric noise low enough to permit detection of planets down to 2 R⊕. We count planets in small domains of Rp and P and divide by the included target stars to calculate planet occurrence in each domain. The resulting occurrence of planets varies by more than three orders of magnitude in the radius–orbital period plane and increases substantially down to the smallest radius (2 R⊕) and out to the longest orbital period (50 days, ∼0.25 AU) in our study. For P < 50 days, the distribution of planet radii is given by a power law, df/dlog R = kRRα with kR = 2.9+0.5− 0.4, α = −1.92 ± 0.11, and R ≡ Rp/R⊕. This rapid increase in planet occurrence with decreasing planet size agrees with the prediction of core-accretion formation but disagrees with population synthesis models that predict a desert at super-Earth and Neptune sizes for close-in orbits. Planets with orbital periods shorter than 2 days are extremely rare; for Rp > 2 R⊕ we measure an occurrence of less than 0.001 planets per star. For all planets with orbital periods less than 50 days, we measure occurrence of 0.130 ± 0.008, 0.023 ± 0.003, and 0.013 ± 0.002 planets per star for planets with radii 2–4, 4–8, and 8–32 R⊕, in agreement with Doppler surveys. We fit occurrence as a function of P to a power-law model with an exponential cutoff below a critical period P0. For smaller planets, P0 has larger values, suggesting that the “parking distance” for migrating planets moves outward with decreasing planet size. We also measured planet occurrence over a broader stellar Teff range of 3600–7100 K, spanning M0 to F2 dwarfs. Over this range, the occurrence of 2–4 R⊕ planets in the Kepler field increases with decreasing Teff, with these small planets being seven times more abundant around cool stars (3600–4100 K) than the hottest stars in our sample (6600–7100 K).

Subfields: Astronomy and Astrophysics, Instrumentation

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Instrumentation

Citations in the corpus

STELLAR AND PLANETARY PROPERTIES OF K2 CAMPAIGN 1 CANDIDATES AND VALIDATION OF 17 PLANETS, INCLUDING A PLANET RECEIVING EARTH-LIKE INSOLATION (2015, methodology): “Like the original mission, we find significantly more small planets than large planets, as expected from the radius distributions measured from Kepler (Howard et al. 2012; Fressin et al. 2013; Morton & Swift 2014).”
THE MASS OF KOI-94d AND A RELATION FOR PLANET RADIUS, MASS, AND INCIDENT FLUX (2013, methodology): “This technique is described in further detail in Howard et al. (2011).”
SWEET-Cat: A catalogue of parameters for Stars With ExoplanETs - I. New atmospheric parameters and masses for 48 stars with planets (2013, background): “Overall, these discoveries are showing that planets are ubiquitous around solar-type stars (e.g. Mayor et al. 2011; Howard et al. 2012).”
Breaking the chains: hot super-Earth systems from migration and disruption of compact resonant chains (2017, background): “First, a fraction of planet pairs are indeed in first-order mean-motion resonance (Lissauer et al. 2011b; Fabrycky et al. 2014).”
Identifying Exoplanets with Deep Learning: A Five-planet Resonant Chain around Kepler-80 and an Eighth Planet around Kepler-90 (2017, background): “…et al. 2016; Thompson et al. 2017; Rowe et al. 2014; Morton et al. 2016), and significantly improved our understanding of the population of small planets in the inner parts of planetary systems (Marcy et al. 2014; Howard et al. 2012; Youdin 2011; Dressing et al. 2015; Wolfgang & Lopez 2015).”
TERRESTRIAL PLANET OCCURRENCE RATES FOR THE KEPLER GK DWARF SAMPLE (2015, methodology): “…7.1 (Borucki et al. 2011b), designate a higher SNR level where the planet sample is close to 100% complete 2 (Catanzarite & Shao 2011; Youdin 2011; Howard et al. 2012; Traub 2012; Dressing & Charbonneau 2013; Dong & Zhu 2013; Silburt et al. 2015), or simultaneously solve for a parameterized…”
A STELLAR-MASS-DEPENDENT DROP IN PLANET OCCURRENCE RATES (2014, methodology): “One striking trend with spectral type that has not yet received full appreciation is the increasing occurrence rate of 2–2.8 Earth radius planets at <50 day orbital periods from low-mass M stars to higher-mass F stars reported by Howard et al. (2012).”
SPECTRAL PROPERTIES OF COOL STARS: EXTENDED ABUNDANCE ANALYSIS OF 1,617 PLANET-SEARCH STARS (2016, background): “…formation is ubiquitous (Burke et al. 2015), that hot jupiters are uncommon (Wang et al. 2015), that super-earths are common around other stars (Howard et al. 2012; Mayor et al. 2011; Howard et al. 2010b), and that unexpected compact systems of planets close to their host stars are common…”
REVISED STELLAR PROPERTIES OF KEPLER TARGETS FOR THE QUARTER 1–16 TRANSIT DETECTION RUN (2013, methodology): “Many studies which have explored planet-occurrence rates using the Kepler sample (e.g., Catanzarite & Shao 2011; Howard et al. 2012; Traub 2012; Dong & Zhu 2013; Fressin et al. 2013; Petigura et al. 2013a,b), have mostly relied on stellar properties based on the Kepler Input Catalog (KIC, Brown et…”
A FRAMEWORK FOR CHARACTERIZING THE ATMOSPHERES OF LOW-MASS LOW-DENSITY TRANSITING PLANETS (2013, methodology): “The ubiquity of these planets has now been shown from Kepler data (Howard et al. 2012; Youdin 2011; Fressin et al. 2013; Dressing & Charbonneau 2013; Morton & Swift 2013).”
A STUDY OF THE SHORTEST-PERIOD PLANETS FOUND WITH KEPLER (2014, methodology): “We do acknowledge that part of the above argument is somewhat circular since we have extrapolated the expression for f (P) from Howard et al. (2012), which was only derived for planets withP > 1 day and all sizes, into the USP range and for small planets.”
SOAR TESS Survey. I. Sculpting of TESS Planetary Systems by Stellar Companions (2019, background): “Kepler probed the large (Howard et al. 2012) and diverse (Lissauer et al. 2011; Welsh et al. 2012) Galactic population of planetary systems but only looked at relatively small regions of the sky at a time.”
A STEEPER THAN LINEAR DISK MASS–STELLAR MASS SCALING RELATION (2016, background): “These include (i) a positive correlation between stellar mass and the occurrence rate of Jovian planets within a few au (e.g., Johnson et al. 2010; Howard et al. 2012; Bonfils et al. 2013), although no correlation is present for the population of hot Jupiters within a 10-day period (Obermeier et…”
An ALMA Survey of Protoplanetary Disks in the σ Orionis Cluster (2017, background): “…with masses between that of Earth and Neptune) appear to be an order of magnitude more abundant than gas giants (i.e., planets with masses several times that of Jupiter), at least for short orbital periods (Howard et al. 2012; Fressin et al. 2013; Petigura et al. 2013; Gaidos et al. 2016).”
A Technique for Extracting Highly Precise Photometry for the Two-Wheeled Kepler Mission (2014, background): “Kepler’s large exoplanet sample has led to statistical analyses of the frequency of exoplanets around solar mass stars (Howard et al. 2012; Youdin 2011; Fressin et al. 2013), around cool stars (Swift et al. 2013; Morton & Swift 2014), and in their stars’ habitable zones (Dressing & Charbonneau…”