Extrasolar planet population synthesis - II. Statistical comparison with observations

By C. Mordasini, Y. Alibert, W. Benz, D. Naef. 2009

272 citations recorded by the source corpus.

Context. This is the second paper in a series of papers showing the results of extrasolar planet population synthesis calculations using our extended core accretion model. In the companion paper (Paper I), we have presented in detail the methods we use. In subsequent papers, we shall discuss the e ect of the host star’s mass on the planetary population and the influence of various properties of protoplanetary disks. Aims. In this second paper, we focus on planets orbiting solar-like stars. The goal is to use the main characteristics of the actually observed extrasolar planet population to derive in a statistical manner constraints on the planet formation models. Methods. Drawing initial conditions for our models at random from probability distributions derived as closely as possible from observations, we synthesize a number of planetary populations. By applying an observational detection bias appropriate for radial velocity surveys, we identify the potentially detectable synthetic planets. The properties of these planets are compared in quantitative statistical tests with the properties of a carefully selected sub-population of actually observed extrasolar planets. Results. We use a two dimensional Kolmogorov-Smirnov test to compare the mass-distance distributions of synthetic and observed planets, as well as the one dimensional version of the test to compare the M sini, the semimajor axis and the [Fe/H] distribution. We find that while many combinations of parameters lead to unacceptable distributions, a number of models can account to a reasonable degree of statistical significance for most of the properties of the observed sample. We concurrently account for many other observed features, e.g. the “metallicity e ect”. This gives us confidence that our model captures several essential features of giant planet formation. In addition, the fact that many parameter combination could be rejected, indicates that planet population synthesis is indeed a promising approach to constrain formation models. Our simulations allow us also to extract a number of properties of the underlying exoplanet population that are not yet directly detectable. For example, we have derived the planetary initial mass function (PIMF) and have been led to conclude that the planets detected so far represent only the tip of the iceberg (9%) of all the existing planets. The PIMF can also be used to predict how the detectable extrasolar planet population will change as the instrumental precision of radial velocity surveys improves from 10 m/s to 1 m/s, or even to an extreme precision of 0.1 m/s.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/b5af5f615c4eb99a13d3cb21974208e660e2e40b

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In Astronomy and Astrophysics

1. Jon Fortney
2. D. Charbonneau
3. Timothy Morton
4. J. Johnson
5. C. Mordasini
6. G. Marcy
7. J. Winn
8. M. Perryman

Citations in the corpus

• PLANET OCCURRENCE WITHIN 0.25 AU OF SOLAR-TYPE STARS FROM KEPLER (2011, background): “The relevant processes, including inward migration, have been simulated numerically both for individual planet growth and for entire populations of planets (Ida & Lin 2004, 2008b; Mordasini et al. 2009a; Schlaufman et al. 2010; Ida & Lin 2010; Alibert et al. 2011).”
• TOWARD A DETERMINISTIC MODEL OF PLANETARY FORMATION. VI. DYNAMICAL INTERACTION AND COAGULATION OF MULTIPLE ROCKY EMBRYOS AND SUPER-EARTH SYSTEMS AROUND SOLAR-TYPE STARS (2010, background): “They have also been reproduced and confirmed by similar population-synthesis approaches (Mordasini et al. 2009) and hybrid (N-body + onedimensional viscous-disk evolution) simulations (Thommes et al. 2008a), albeit some differences in the asymptotic Mp–”
• COLLISIONS BETWEEN GRAVITY-DOMINATED BODIES. II. THE DIVERSITY OF IMPACT OUTCOMES DURING THE END STAGE OF PLANET FORMATION (2011, methodology): “…purpose of this Monte Carlo simulation is to investigate the effects of the collision physics model and is not meant to replace full N -body planet formation models or more sophisticated statistical population synthesis models (e.g., Alibert et al. 2011; Mordasini et al. 2009a,b; Ida & Lin 2010).”
• PARTICLE CLUMPING AND PLANETESIMAL FORMATION DEPEND STRONGLY ON METALLICITY (2009, background): “The correlation between host star metallicity and giant exoplanets can be partly attributed to the efficiency of forming several-Earth-mass cores from planetesimals (Ida & Lin 2004; Mordasini et al. 2009).”
• Characterization of exoplanets from their formation - I. Models of combined planet formation and evolution (2012, methodology): “Migration is also completely switched off, otherwise, it is a central component of the formation model as it can lead to much more complex accretion histories (Mordasini et al. 2009a).”
• Extrasolar planet population synthesis - IV. Correlations with disk metallicity, mass, and lifetime (2012, methodology): “They indicate (e.g. Mordasini et al. 2009a) that runaway bodies should emerge with a uniform distribution in log(astart), as already adopted by Ida & Lin (2004a).”
• Characterization of exoplanets from their formation - II. The planetary mass-radius relationship (2012, methodology): “self-gravity In population synthesis calculations (e.g. Ida & Lin 2004; Mordasini et al. 2009a) one uses distributions of (initial) protoplanetary disk masses in order to reflect the varying initial conditions for planet formation.”
• GIANT PLANET MIGRATION, DISK EVOLUTION, AND THE ORIGIN OF TRANSITIONAL DISKS (2009, methodology): “…density, accretion rate, etc.) of every model are known throughout, and this “brute force” method allows us to study the effects of migrating planets on the disk population in a manner that is not possible using more typical population synthesis methods (Ida& Lin 2004a,b; Mordasini et al. 2009a,b).”
• SOPHIE velocimetry of Kepler transit candidates XVII. The physical properties of giant exoplanets within 400 days of period (2015, methodology): “As an example, both the well-adopted core – accretion model (e.g. Mordasini et al. 2009b) and the latest results from the disk – instability model (e.g. Nayakshin 2014, 2015) are able to reproduce the observed correlation of ?”
• Wide-Field InfrarRed Survey Telescope-Astrophysics Focused Telescope Assets WFIRST-AFTA 2015 Report (2015, background): “Furthermore, this parameter space is largely disjoint from both the planets in our solar system, and from the three largest reservoirs of planets that are predicted by many planet formation theories (e.g. Ida & Lin 2004, Mordasini et al. 2009).”
• Hints for a Turnover at the Snow Line in the Giant Planet Occurrence Rate (2018, background): “Core-accretion planet formation models that include disk migration typically predict that the occurrence of giant planets increases with distance from the star within ∼1 au (e.g., Ida & Lin 2004a; Mordasini et al. 2009) but often show a break at larger distances.”
• A COLD NEPTUNE-MASS PLANET OGLE-2007-BLG-368Lb: Cold neptunes are common (2009, background): “This is also steeper than the mass function prediction of Mordasini et al. (2009) for solar-type stars, although this theoretical mass function is not a power law.”
• Planet-Disk Interaction and Orbital Evolution (2012, background): “Mordasini, Alibert & Benz (2009) and Mordasini et al. (2009) present models with full-strength type I migration that are able to form a sparse population of gas giants.”