A STELLAR-MASS-DEPENDENT DROP IN PLANET OCCURRENCE RATES

By G. Mulders, Ilaria Pascucci, D. Apai. 2014

146 citations recorded by the source corpus.

The Kepler spacecraft has discovered a large number of planets with up to one-year periods and down to terrestrial sizes. While the majority of the target stars are main-sequence dwarfs of spectral type F, G, and K, Kepler covers stars with effective temperatures as low as 2500 K, which corresponds to M stars. These cooler stars allow characterization of small planets near the habitable zone, yet it is not clear if this population is representative of that around FGK stars. In this paper, we calculate the occurrence of planets around stars of different spectral types as a function of planet radius and distance from the star and show that they are significantly different from each other. We further identify two trends. First, the occurrence of Earth- to Neptune-sized planets (1–4 R⊕) is successively higher toward later spectral types at all orbital periods probed by Kepler; planets around M stars occur twice as frequently as around G stars, and thrice as frequently as around F stars. Second, a drop in planet occurrence is evident at all spectral types inward of a ∼10 day orbital period, with a plateau further out. By assigning to each spectral type a median stellar mass, we show that the distance from the star where this drop occurs is stellar mass dependent, and scales with semi-major axis as the cube root of stellar mass. By comparing different mechanisms of planet formation, trapping, and destruction, we find that this scaling best matches the location of the pre-main-sequence co-rotation radius, indicating efficient trapping of migrating planets or planetary building blocks close to the star. These results demonstrate the stellar-mass dependence of the planet population, both in terms of occurrence rate and of orbital distribution. The prominent stellar-mass dependence of the inner boundary of the planet population shows that the formation or migration of planets is sensitive to the stellar parameters.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/833fb03bf4861d932412ce21679e0163fe789b6a

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Citations in the corpus

The Habitability of Planets Orbiting M-dwarf Stars (2016, background): “Considering the higher planet-occurrence rate for M-dwarf stars (Howard et al., 2012b; Mulders et al., 2015b), water-rich terrestrial planets could dominate around M-dwarf stars.”
Identifying Exoplanets with Deep Learning: A Five-planet Resonant Chain around Kepler-80 and an Eighth Planet around Kepler-90 (2017, background): “As the Kepler mission matured and the list of planet candidates grew, the focus of the community shifted towards population-level studies (Fressin et al. 2013; Petigura et al. 2013a,b; Foreman-Mackey et al. 2014; Dressing & Charbonneau 2013, 2015; Burke et al. 2015; Mulders et al. 2015a,b).”
ZODIACAL EXOPLANETS IN TIME (ZEIT). III. A SHORT-PERIOD PLANET ORBITING A PRE-MAIN-SEQUENCE STAR IN THE UPPER SCORPIUS OB ASSOCIATION (2016, background): “Most planets around M dwarfs found by Kepler are 1-2.5R⊕ (Morton & Swift 2014; Mulders et al. 2015; Dressing & Charbonneau 2015; Gaidos et al. 2016b), while K2-33b is roughly twice this size at 5.04+0.34−0.37 R⊕.”
IN SITU FORMATION AND DYNAMICAL EVOLUTION OF HOT JUPITER SYSTEMS (2015, background): “Instead, hot “SuperEarths,” planets with P < 100 days and m < 30M⊕ are extremely common, with 30-50% of main sequence stars in the solar neighborhood serving as hosts (Fressin et al. 2013; Dressing and Charbonneau 2013, 2015; Petigura et al. 2013; Mulders et al. 2015; Winn and Fabrycky 2015).”
A STEEPER THAN LINEAR DISK MASS–STELLAR MASS SCALING RELATION (2016, methodology): “…et al. 2013), although no correlation is present for the population of hot Jupiters within a 10-day period (Obermeier et al. 2016); and (ii) a larger occurrence rate of close-in Earth-sized planets around M dwarfs than around Sun-like stars (Dressing & Charbonneau 2013; Mulders et al. 2015a).”
The Exoplanet Population Observation Simulator. I. The Inner Edges of Planetary Systems (2018, methodology): “We evaluate the survey as a whole, and do not consider dependencies on stellar properties such as stellar mass (Mulders et al. 2015a, 2015b) or metallicity (Mulders et al. 2016; Petigura et al. 2018).”
Hints for a Turnover at the Snow Line in the Giant Planet Occurrence Rate (2018, background): “In disks around young solar analogues, the snow line is expected to be between ∼2- 5 au (e.g., Mulders et al. 2015a).”
TERRESTRIAL PLANET OCCURRENCE RATES FOR THE KEPLER GK DWARF SAMPLE (2015, methodology): “…(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 completeness model in addition to planet occurrence (Fressin et al. 2013; Mulders et al. 2015; Farr et al. 2014).”
How Hospitable Are Space Weather Affected Habitable Zones? The Role of Ion Escape (2017, unknown): “Kepler data suggest that the occurrence rates of terrestrial planets ( with radii between 1 and 4 R Earh ) are 0.3, 0.2, and 0.1 planet per star for M, K, and G dwarfs, respectively ( Mulders et al. 2015 ) .”
The California-Kepler Survey. IV. Metal-rich Stars Host a Greater Diversity of Planets (2017, unknown): “…& Shao (2011); Traub (2012); Howard et al. (2012); Fressin et al. (2013); Dong & Zhu (2013); Petigura et al. (2013); ForemanMackey et al. (2014); Burke et al. (2015); Dressing & Charbonneau (2015); Mulders et al. (2015). and with the occurrence of large planets (RP > 1.7 R⊕, P < 100 days).”