Tidal Downsizing Model. III. Planets from sub-Earths to Brown Dwarfs: structure and metallicity preferences

Abstract

We present population synthesis calculations of the Tidal Downsizing (TD) hypothesis for planet formation. Our models address the following observations: (i) most abundant planets being Super Earths; (ii) cores more massive than $\sim 5-15M_{\oplus }$ are enveloped by massive atmospheres; (iii) the frequency of occurrence of close-in gas giant planets correlates strongly with metallicity of the host star; (iv) no such correlation is found for sub-Neptune planets; (v) presence of massive cores in giant planets; (vi) gas giant planets are over-abundant in metals compared to their host stars; (vii) this over-abundance decreases with planet's mass; (viii) a deep valley in the planet mass function between masses of $\sim 10-20M_{\oplus }$ and $\sim 100M_{\oplus }$. A number of observational predictions distinguish the model from Core Accretion: (a) composition of the massive cores is always dominated by rocks not ices; (b) the core mass function is smooth with no minimum at $\sim 3M_{\oplus }$ and has no ice-dominated cores; (c) gas giants beyond 10 AU are insensitive to the host star metallicity; (d) objects more massive than $\sim 10M_{\mathrm{Jup}}$ do not correlate or even anti-correlate with metallicity. The latter prediction is consistent with observations of low mass stellar companions. TD can also explain formation of planets in close binary systems. TD model is a viable alternative to the Core Accretion scenario in explaining many features of the observed population of exoplanets.

Final version accepted by MNRAS. 26 pages

References in corpus (21)

• Spectroscopic parameters for 451 stars in the HARPS GTO planet search program. Stellar [Fe/H] and the frequency of exo-Neptunes
• On the Luminosity of Young Jupiters
• The Transiting Circumbinary Planets Kepler-34 and Kepler-35
• Separating gas-giant and ice-giant planets by halting pebble accretion
• The Burst Mode of Protostellar Accretion
• Dust dynamics during protoplanetary disc clearing
• Planets Around Low-Mass Stars (PALMS). IV. The Outer Architecture of M Dwarf Planetary Systems
• Variable protostellar accretion with episodic bursts
• The Photoevaporation of Discs Around Young Stars in Massive Clusters
• A Statistical Reconstruction of the Planet Population Around Kepler Solar-Type Stars
• Can giant planets form by gravitational fragmentation of discs?
• Global Models of Planet Formation and Evolution
• Planetesimal and gas dynamics in binaries
• Core Formation in Giant Gaseous Protoplanets
• Grain Sedimentation in a Giant Gaseous Protoplanet
• Deserts and pile-ups in the distribution of exoplanets due to photoevaporative disc clearing
• The properties of discs around planets and brown dwarfs as evidence for disc fragmentation
• The Formation of Uranus & Neptune: Challenges and Implications For Intermediate-Mass Exoplanets
• Core-assisted gas capture instability: a new mode of giant planet formation by gravitationally unstable discs
• Positive metallicity correlation for coreless giant planets
• Metal loading of giant gas planets

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• EPIC201702477b: A Long Period Transiting Brown Dwarf from K2
• On the diversity in mass and orbital radius of giant planets formed via disk instability
• Giant planets and brown dwarfs on wide orbits: a code comparison project
• Changes in the metallicity of gas giant planets due to pebble accretion
• Binary companions triggering fragmentation in self-gravitating discs
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• Constraining the initial planetary population in the gravitational instability model
• The chemical composition of planet building blocks as predicted by stellar population synthesis
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• AB Aurigae: Possible evidence of planet formation through the gravitational instability
• ALMA constraints on assembly of Core Accretion planets
• The burst mode of accretion in massive star formation with stellar inertia
• DIPSY: A new Disc Instability Population SYnthesis, II. The Populations of Companions Formed Through Disc Instability
• Populations of Extrasolar Giant Planets from Transit and Radial Velocity Surveys
• Calibrated Gas Accretion and Orbital Migration of Protoplanets in 1D Disc Models
• Searching for wide-orbit gravitational instability protoplanets with ALMA in the dust continuum
• The paradox of youth for ALMA planet candidates
• DIPSY: A new Disc Instability Population SYnthesis, I. Modeling, evolution of individual systems, and tests
• Planets, debris and their host metallicity correlations
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