Characterization of exoplanets from their formation - I. Models of combined planet formation and evolution

By C. Mordasini, Y. Alibert, H. Klahr, Th. Henning. 2012

231 citations recorded by the source corpus.

Context. A first characterization of extrasolar planets by the observational determination of the radius has recently been achieved for a large number of planets. For some planets, a measurement of the luminosity has also been possible, with many more directly imaged planets expected in the near future. The statistical characterization of exoplanets through their mass-radius and mass-luminosity diagram is becoming possible. This is for planet formation and evolution theory of similar importance as the mass-distance diagram. Aims. Our aim is to extend our planet-formation model into a coupled formation and evolution model. We want to calculate from one single model in a self-consistent way all basic quantities describing a planet: its mass, semimajor axis, composition, radius, and luminosity. We then want to use this model for population synthesis calculations. Methods. In this and a companion paper, we show how we solve the structure equations describing the gaseous envelope of a protoplanet during the early-formation phase, the gas runaway accretion phase, and the evolutionary phase at constant mass on Gyr timescales. We improve the model further with a new prescription for the disk-limited gas accretion rate, an internal structure model for the planetary core assuming a differentiated interior, and the inclusion of radioactive decay as an additional heat source in the core. Results. We study the in situ formation and evolution of Jupiter, the mass-radius relationship of giant planets, the influence of the core mass on the radius, and the luminosity both in the “hot start” and the “cold start” scenario. Special emphasis is placed on the validation of the model by comparing it with other models of planet formation and evolution. We find that our results agree very well with those of more complex models, despite a number of simplifications we make in our calculations. Conclusions. The upgraded model yields the most important physical quantities describing a planet from its beginning as a tiny seed embryo to a Gyr-old planet. This is the case for all planets in a synthetic planetary population. Therefore, we can now use selfconsistently the observational constraints coming from all major observational techniques. This is important in a time where different techniques yield constraints on very diverse sub-populations of planets, and where it is difficult to put all these constraints together in one coherent picture. Our comprehensive formation and evolution model should be helpful in this situation for the understanding of exoplanets.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/06c0d4b48d2ceee2546848b7b5b1663be94421b8

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In Astronomy and Astrophysics

1. Jon Fortney
2. N. Madhusudhan
3. C. Mordasini
4. Th. Henning
5. S. Andrews
6. D. Wilner
7. T. Birnstiel
8. J. Owen

In Instrumentation

1. Jon Fortney
2. N. Madhusudhan
3. C. Mordasini
4. V. Parmentier
5. M. Marley
6. J. Owen
7. Th. Henning
8. S. Andrews

Citations in the corpus

• Characterization of exoplanets from their formation - II. The planetary mass-radius relationship (2012, methodology): “This value has been determined in Mordasini et al. (2012c) by comparison with detailed grain evolution calculations in protoplanetary envelopes (Movshovitz et al. 2010).”
• A FRAMEWORK FOR CHARACTERIZING THE ATMOSPHERES OF LOW-MASS LOW-DENSITY TRANSITING PLANETS (2013, methodology): “The planets are synthesized using an upgraded version (Mordasini et al. 2012b) of the planet formation model originally presented in Alibert et al. (2004).”
• GASEOUS MEAN OPACITIES FOR GIANT PLANET AND ULTRACOOL DWARF ATMOSPHERES OVER A RANGE OF METALLICITIES AND TEMPERATURES (2014, background): “These tabulations have since found wide use in the communities working to understand giant planet formation (e.g., Mordasini et al. 2012; Bodenheimer et al. 2013), the temperature structure of giant planet atmospheres (e.g. Paxton etal.”
• 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).”
• Three Radial Gaps in the Disk of TW Hydrae Imaged with SPHERE (2016, methodology): “In order to assess this question, we analyzed the CD753 population from Mordasini et al. (2012), which can be interactively inspected at https://dace.unige.ch/ evolution/index#.”
• THE IMPRINT OF EXOPLANET FORMATION HISTORY ON OBSERVABLE PRESENT-DAY SPECTRA OF HOT JUPITERS (2016, methodology): “The model has been described in detail in several previous works (Alibert et al. 2004, 2005, Mordasini et al. 2012c) with a recent overview in Mordasini et al. (2015).”
• Imaging Extrasolar Giant Planets (2016, background): “The treatment of accretion shocks, circumplanetary disks, core mass, and even deuterium burning for the most massive planets can dramatically influence the initial entropy and luminosity evolution of planets (Mordasini et al. 2012; Bodenheimer et al. 2013; Mordasini 2013; Owen & Menou 2016).”
• Retrieving scattering clouds and disequilibrium chemistry in the atmosphere of HR 8799e (2020, background): “For ages up to 5 Gyr, radii are above 1 RJ for masses up to 30 MJ (Mordasini et al. 2012).”
• The Disk Substructures at High Angular Resolution Project (DSHARP). II. Characteristics of Annular Substructures (2018, background): “These wide Corresponding author: Jane Huang jane.huang@cfa.harvard.edu variations in properties are thought to be closely tied to differences in where and when planets formed in the protoplanetary disks orbiting young stars (e.g., Öberg et al. 2011b; Mordasini et al. 2012; Lee & Chiang 2016).”
• A YOUNG PROTOPLANET CANDIDATE EMBEDDED IN THE CIRCUMSTELLAR DISK OF HD 100546 (2013, background): “Young, forming gas giants with masses between one and a few Jupiter masses are expected to have luminosities between 10−4– 10−2L⊙ during the first few hundred thousand years after gas runaway accretion sets in (Mordasini et al. 2012), in agreement with our lower limit.”
• CHARACTERIZING TRANSITING EXOPLANET ATMOSPHERES WITH JWST (2015, methodology): “Using population synthesis models (Mordasini et al. 2012), Fortney et al. (2013) suggests that as the mass of a planet decreases, the atmospheric metallicity increases.”
• PLANETARY POPULATION SYNTHESIS COUPLED WITH ATMOSPHERIC ESCAPE: A STATISTICAL VIEW OF EVAPORATION (2014, methodology): “We assume that the luminosity is constant with radius, which does not significantly affect the evolution as discussed in Mordasini et al. (2012a).”
• Compositional Imprints in Density–Distance–Time: A Rocky Composition for Close-in Low-mass Exoplanets from the Location of the Valley of Evaporation (2017, methodology): “Such low-mass planets can have a large radius even with a tenuous envelope (Adams et al. 2008; Rogers et al. 2011; Mordasini et al. 2012b), and can be easily evaporated to bare cores at close-in orbits (Lopez & Fortney 2013; Jin et al. 2014).”