Theoretical vs. observational uncertainties: composition of giant exoplanets

Abstract

In order to characterize giant exoplanets and better understand their origin, knowledge of how the planet's composition depends on its mass and stellar environment is required. In this work, we simulate the thermal evolution of gaseous planets and explore how various common model assumptions such as different equations of state, opacities, and heavy-element distributions affect the inferred radius and metallicity. We examine how the theoretical uncertainties translate into uncertainties in the inferred planetary radius and bulk metallicity. While we confirm the mass-metallicity trend previously reported in the literature, this correlation disappears when removing a 20 $M_{\oplus }$ heavy-element core from all the planets. We also show that using an updated hydrogen-helium equation of state leads to more compact planets. As a result, we present six planets that should be classified as inflated warm Jupiters. We next demonstrate that including the opacity-enhancement due to metal-rich envelopes of irradiated planets changes the planetary radius significantly, which can have large effects on the inferred metallicity. Even though there are other model assumptions that have not been considered in this work, we could show that the calculated theoretical uncertainties can already be comparable or even larger than the observational ones. Therefore, theoretical uncertainties are likely to be even larger. We therefore conclude that progress in theoretical models of giant planets is essential in order to take full advantage of current and future exoplanetary data.

25 pages, 9 figures, 2 tables, accepted for publication in ApJ

References in corpus (20)

• Modules for Experiments in Stellar Astrophysics (MESA)
• The James Webb Space Telescope
• Modules for Experiments in Stellar Astrophysics (MESA): Pulsating Variable Stars, Rotation, Convective Boundaries, and Energy Conservation
• On the radiative equilibrium of irradiated planetary atmospheres
• On the Luminosity of Young Jupiters
• Updated Electron-Conduction Opacities: The Impact on Low-Mass Stellar Models
• The Mass of KOI-94d and a Relation for Planet Radius, Mass, and Incident Flux
• Formation of Jupiter using opacities based on detailed grain physics
• A new equation of state for dense hydrogen-helium mixtures
• Ab initio equations of state for hydrogen (H-REOS.3) and helium (He-REOS.3) and their implications for the interior of Brown Dwarfs
• Grain opacity and the bulk composition of extrasolar planets. II. An analytical model for the grain opacity in protoplanetary atmospheres
• The Challenge of Forming a Fuzzy Core in Jupiter
• The origin of the high metallicity of close-in giant exoplanets: Combined effect of the resonant and aerodynamic shepherding
• An analysis of the CoRoT-2 system: A young spotted star and its inflated giant planet
• Convection and Mixing in Giant Planet Evolution
• Jupiter's heavy-element enrichment expected from formation models
• Do Metal-Rich Stars Make Metal-Rich Planets? New Insights on Giant Planet Formation from Host Star Abundances
• The maximum mass of planetary embryos formed in core-accretion models
• Giant planet formation models with a self-consistent treatment of the heavy elements
• Heavy-metal Jupiters by major mergers: metallicity vs. mass for giant planets

Cited by in corpus (23)

• The New Generation Planetary Population Synthesis (NGPPS). I. Bern global model of planet formation and evolution, model tests, and emerging planetary systems
• How drifting and evaporating pebbles shape giant planets I: Heavy element content and atmospheric C/O
• The mass-radius relation of exoplanets, revisited
• A transiting warm giant planet around the young active star TOI-201
• Synthetic Evolution Tracks of Giant Planets
• Towards a new era in giant exoplanet characterisation
• Constraining the origin of giant exoplanets via elemental abundance measurements
• Convective Mixing in Gas Giant Planets with Primordial Composition Gradients
• Revising the Giant Planet Mass-Metallicity Relation: Deciphering the Formation Sequence of Giant Planets
• Ariel Planetary Interiors White Paper
• Giant exoplanet composition: Why do the hydrogen-helium equation of state and interior structure matter?
• Shallowness of circulation in hot Jupiters -- Advancing the Ohmic dissipation model
• Giant Outer Transiting Exoplanet Mass (GOT 'EM) Survey. II. Discovery of a Failed Hot Jupiter on a 2.7 Year, Highly Eccentric Orbit
• Why do more massive stars host larger planets?
• The bulk metallicity of giant planets around M stars
• The effect of cloudy atmospheres on the thermal evolution of warm giant planets from an interior modelling perspective
• On the origin of Jupiter's fuzzy core: constraints from N-body, impact and evolution simulations
• GEMS JWST: Transmission spectroscopy of TOI-5205b reveals significant stellar contamination and a metal-poor atmosphere
• Multi-band reflectance and shadowing of RX J1604.3-2130 protoplanetary disk in scattered light
• Detection and characterisation of a 106-day transiting Jupiter : TOI-2449 b / NGTS-36 b
• How Internal Structure Shapes the Metallicity of Giant Exoplanets
• The Evolution and Internal Structure of Neptunes and Sub-Neptunes: The importance of thermal conductivity in non-convective regions
• Excitation and Damping of Oscillation Modes in Gaseous Planets