TESTING IN SITU ASSEMBLY WITH THE KEPLER PLANET CANDIDATE SAMPLE

By Brad M. S. Hansen, N. Murray. 2013

172 citations recorded by the source corpus.

We present a Monte Carlo model for the structure of low-mass (total mass <25 M⊕) planetary systems that form by the in situ gravitational assembly of planetary embryos into final planets. Our model includes distributions of mass, eccentricity, inclination, and period spacing that are based on the simulation of a disk of 20 M⊕, forming planets around a solar-mass star, and assuming a power-law surface density distribution that drops with distance a as ∝ a−1.5. The output of the Monte Carlo model is then subjected to the selection effects that mimic the observations of a transiting planet search such as that performed by the Kepler satellite. The resulting comparison of the output to the properties of the observed sample yields an encouraging agreement in terms of the relative frequencies of multiple-planet systems and the distribution of the mutual inclinations when moderate tidal circularization is taken into account. The broad features of the period distribution and radius distribution can also be matched within this framework, although the model underpredicts the distribution of small period ratios. This likely indicates that some dissipation is still required in the formation process. The most striking deviation between the model and observations is in the ratio of single to multiple systems in that there are roughly 50% more single-planet candidates observed than are produced in any model population. This suggests that some systems must suffer additional attrition to reduce the number of planets or increase the range of inclinations.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/e0f6a3e444e96c22e33300605dda3f30e92c1f88

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

1. Timothy Morton
2. J. Owen
3. D. Charbonneau
4. E. Petigura
5. G. Marcy
6. J. Johnson
7. Andrew W. Howard
8. Jon Fortney

In Instrumentation

1. J. Owen
2. Timothy Morton
3. E. Petigura
4. D. Charbonneau
5. G. Marcy
6. Jon Fortney
7. Andrew W. Howard
8. J. Winn

Citations in the corpus

• They are small worlds after all: revised properties of Kepler M dwarf stars and their planets (2015, unknown): “Previous analyses of solar-type Kepler stars have likewise found that the best-fit single-population models for planets around solar-type stars significantly under-predict the number of single-transit systems (Lissauer et al. 2011; Hansen & Murray 2013).”
• The California-Kepler Survey. IV. Metal-rich Stars Host a Greater Diversity of Planets (2017, background): “In Situ Formation The prevalence of compact multi-planet systems of super-Earths/sub-Neptunes discovered by Kepler helped inspire in situ planet formation models (see e.g. Hansen & Murray 2013 and Chiang & Laughlin 2013).”
• THE RADIUS DISTRIBUTION OF PLANETS AROUND COOL STARS (2013, background): “…number of single versus multi-transit systems provides constraints on the number of planets in a given system within Kepler ’s discovery window, else it may be the first indication of a separate, high-inclination population of single transit systems (Hansen & Murray 2013; Fang & Margot 2012).”
• UNDERSTANDING THE MASS–RADIUS RELATION FOR SUB-NEPTUNES: RADIUS AS A PROXY FOR COMPOSITION (2013, background): “Are these Neptune-like planets that form beyond the snow-line and contain large amounts of volatile ices (Rogers et al. 2011), or are these scaled up terrestrial worlds with H/He envelopes that formed close to their current orbits (Hansen & Murray 2013; Chiang & Laughlin 2013)?”
• KEPLER PLANETS: A TALE OF EVAPORATION (2013, background): “It is at this point that we will begin to learn valuable information about the planet population at birth and make inferences about the planet formation process (e.g Ida & Lin 2005; Mordasini et al. 2012a,b; Hansen & Murray 2012, 2013).”
• PLANETARY CANDIDATES OBSERVED BY KEPLER IV: PLANET SAMPLE FROM Q1–Q8 (22 MONTHS) (2013, background): “…of multiple planet candidate systems provides insight into the formation, migration, and dynamical interaction processes that result in the planets observed by Kepler (e.g., Ford et al. 2011; Lissauer et al. 2011b; Fabrycky et al. 2012b; Rein 2012; Hansen & Murray 2013; Batygin & Morbidelli 2013).”
• The California-Kepler Survey. V. Peas in a Pod: Planets in a Kepler Multi-planet System Are Similar in Size and Regularly Spaced (2017, background): “The observed and statistically inferred orbital properties in multi-planet systems have been used to deduce possible planet formation histories (Fang & Margot 2012; Hansen & Murray 2013; Steffen & Hwang 2015; Malhotra 2015; Pu & Wu 2015; Ballard & Johnson 2016; Xie et al. 2016). ar X iv :1 70 6.”
• The Exoplanet Population Observation Simulator. I. The Inner Edges of Planetary Systems (2018, background): “The occurrence rates and planetary architectures place strong constraints on planet formation models (e.g., Hansen & Murray 2013; Dawson et al. 2016).”
• About 30% of Sun-like Stars Have Kepler-like Planetary Systems: A Study of Their Intrinsic Architecture (2018, methodology): “Second, Hansen & Murray (2013) noted that their simulations predicted too few single tranet systems.”
• The Habitability of Planets Orbiting M-dwarf Stars (2016, background): “However,the best–fitting models to the Kepler yield underpredict the number of singly–transiting systems by a factor of two (Lissauer et al., 2011; Hansen & Murray, 2013).”
• Breaking the chains: hot super-Earth systems from migration and disruption of compact resonant chains (2017, background): “…standard in situ accretion models that invoke high-mass discs from the beginning to allow multi-Earth masses planets to form in the inner regions (Hansen & Murray 2012, 2013); and (b) drift-then-assembly model which proposes that these planets form in the innermost regions of the disc in…”
• MAKE SUPER-EARTHS, NOT JUPITERS: ACCRETING NEBULAR GAS ONTO SOLID CORES AT 0.1 AU AND BEYOND (2014, methodology): “But closer to the star, the universe of possibilities narrows considerably, assuming that planets form in-situ (Hansen & Murray 2012, 2013; Chiang & Laughlin 2013).”