Prevalence of Earth-size planets orbiting Sun-like stars

By E. Petigura, Andrew W. Howard, G. Marcy. 2013

703 citations recorded by the source corpus.

Significance A major question is whether planets suitable for biochemistry are common or rare in the universe. Small rocky planets with liquid water enjoy key ingredients for biology. We used the National Aeronautics and Space Administration Kepler telescope to survey 42,000 Sun-like stars for periodic dimmings that occur when a planet crosses in front of its host star. We found 603 planets, 10 of which are Earth size and orbit in the habitable zone, where conditions permit surface liquid water. We measured the detectability of these planets by injecting synthetic planet-caused dimmings into Kepler brightness measurements. We find that 22% of Sun-like stars harbor Earth-size planets orbiting in their habitable zones. The nearest such planet may be within 12 light-years. Determining whether Earth-like planets are common or rare looms as a touchstone in the question of life in the universe. We searched for Earth-size planets that cross in front of their host stars by examining the brightness measurements of 42,000 stars from National Aeronautics and Space Administration’s Kepler mission. We found 603 planets, including 10 that are Earth size () and receive comparable levels of stellar energy to that of Earth (). We account for Kepler’s imperfect detectability of such planets by injecting synthetic planet–caused dimmings into the Kepler brightness measurements and recording the fraction detected. We find that 11 ± 4% of Sun-like stars harbor an Earth-size planet receiving between one and four times the stellar intensity as Earth. We also find that the occurrence of Earth-size planets is constant with increasing orbital period (P), within equal intervals of logP up to ∼200 d. Extrapolating, one finds % of Sun-like stars harbor an Earth-size planet with orbital periods of 200–400 d.

Subfields: Astronomy and Astrophysics

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Citations in the corpus

A SYSTEMATIC SEARCH FOR TRANSITING PLANETS IN THE K2 DATA (2015, methodology): “This project follows in the tradition of independently implemented transit search algo- rithms applied to publicly available datasets (such as Petigura et al. 2013b,a; Sanchis-Ojeda et al. 2014; Dressing & Charbonneau 2015).”
THE RADIUS DISTRIBUTION OF PLANETS AROUND COOL STARS (2013, methodology): “Dressing & Charbonneau (2013) claim that the occurrence rate begins to decrease for planets smaller than 1-1.4 R⊕, and Petigura et al. (2013) find that the planet occurrence rate decreases for planets smaller than 2 R⊕.”
The California-Kepler Survey. II. Precise Physical Properties of 2025 Kepler Planets and Their Host Stars (2017, background): “This large sample of planets with high purity enabled studies of planet occurrence (Howard et al. 2012; Fressin et al. 2013; Petigura et al. 2013) and planetary architectures (Lissauer et al. 2011; Fabrycky et al. 2014), and when coupled with spectroscopy, enabled determination of planet masses,…”
Observing the Atmospheres of Known Temperate Earth-sized Planets with JWST (2017, background): “Planets smaller than Neptune are now known to be common around both sunlike stars and cooler M dwarfs (Petigura et al. 2013; Burke et al. 2015; Dressing & Charbonneau 2015), with the Kepler mission revealing thousands of planet candidates around distant stars (Borucki et al. 2011; Coughlin et al.…”
LOW FALSE POSITIVE RATE OF KEPLER CANDIDATES ESTIMATED FROM A COMBINATION OF SPITZER AND FOLLOW-UP OBSERVATIONS (2015, background): “…also necessary for determining the occurrence rate of exoplanets (e.g., Howard et al. 2012; Fressin et al. 2013), and more specifically of Earth-size planets in the habitable zone of their parent stars (e.g., Catanzarite & Shao 2011; Traub 2012; Petigura et al. 2013; Dressing & Charbonneau 2013).”
FALSE POSITIVE PROBABILITIES FOR ALL KEPLER OBJECTS OF INTEREST: 1284 NEWLY VALIDATED PLANETS AND 428 LIKELY FALSE POSITIVES (2016, background): “And perhaps most notably, it has enabled for the first time estimates of the occurrence rates of small planets (&1 R⊕) out to orbits of about one year (e.g. Petigura et al. 2013; Foreman-Mackey et al. 2014; Burke et al. 2015).”
ECCENTRICITY FROM TRANSIT PHOTOMETRY: SMALL PLANETS IN KEPLER MULTI-PLANET SYSTEMS HAVE LOW ECCENTRICITIES (2015, background): “These effects are important when comparing occurrence rates of different types of planets but have so far not been taken into account (Petigura et al. 2013; Foreman-Mackey et al. 2014).”
MAXIMIZING THE ExoEarth CANDIDATE YIELD FROM A FUTURE DIRECT IMAGING MISSION (2014, methodology): “We started by simulating 105 exoEarths around a Sun-like star at 1 pc using the planet parameters listed in Table 1.”
FRIENDS OF HOT JUPITERS. I. A RADIAL VELOCITY SEARCH FOR MASSIVE, LONG-PERIOD COMPANIONS TO CLOSE-IN GAS GIANT PLANETS (2013, background): “They also note that this number is most likely an underestimate, as the occurrence rates for planets increase sharply towards smaller masses and radii (e.g., Howard et al. 2010; Petigura et al. 2013) where their survey has a high level of incompleteness.”
The K2 Mission: Characterization and Early Results (2014, background): “The incidence of short-period planets around field stars (Fressin et al. 2013; Petigura et al. 2013) suggests that a few transiting hot Jupiters and Neptunes will be found per campaign, as well as several tens of Super-Earths and smaller planets assuming ∼1500 cluster members are observed (see §…”
Kepler Planet Masses and Eccentricities from TTV Analysis (2016, background): “Small planets with radii in the range R R1 4p = Å– on short-period orbits, P 100< days, are among the most abundant, occurring around roughly half of Sun-like stars (e.g., Fressin et al. 2013; Petigura et al. 2013).”
The California-Kepler Survey. III. A Gap in the Radius Distribution of Small Planets (2017, methodology): “Following the definitions in Petigura et al. (2013a), the average planet occurrence rate (number of planets per star) for any discrete bin in planet radius or orbital period is the sum of these weights divided by the total number of stars in the sample (N?)”
A NEARBY M STAR WITH THREE TRANSITING SUPER-EARTHS DISCOVERED BY K2 (2015, methodology): “1a) using the TERRA algorithm described in Petigura et al. (2013).”
About 30% of Sun-like Stars Have Kepler-like Planetary Systems: A Study of Their Intrinsic Architecture (2018, methodology): “(23) This is a factor of ∼two lower than previous estimates (Fressin et al. 2013; Petigura et al. 2013; Winn & Fabrycky 2015).”