GASTLI: An open-source coupled interior-atmosphere model to unveil gas giant composition

Abstract

The metal mass fractions of gas giants are a powerful tool to constrain their formation mechanisms and evolution. The metal content is inferred by comparing mass and radius measurements with interior structure and evolution models. In the midst of the JWST, CHEOPS, TESS, and the forthcoming PLATO era, we are at the brink of obtaining unprecedented precision in radius, age and atmospheric metallicity measurements. To prepare for this wealth of data, we present the GAS gianT modeL for Interiors (GASTLI), an easy-to-use, publicly available Python package. The code is optimized to rapidly calculate mass-radius relations, and radius and luminosity thermal evolution curves for a variety of envelope compositions and core mass fractions. Its applicability spans planets with masses $17M_{\oplus }<M<6M_{Jup}$, and equilibrium temperatures $T_{eq}<1000$ K. The interior model is stratified in a core composed of water and rock, and an envelope constituted by H/He and metals (water). The interior is coupled to a grid of self-consistent, cloud-free atmospheric models to determine the atmospheric and boundary interior temperature, as well as the contribution of the atmosphere to the total radius. We successfully validate GASTLI by comparing it to previous work and data of the Solar System's gas giants and Neptune. We also test GASTLI on the Neptune-mass exoplanet HAT-P-26 b, finding a bulk metal mass fraction between 0.60-0.78 and a core mass of 8.5-14.4 $M_{\oplus }$. Finally, we explore the impact of different equations of state and assumptions, such as C/O ratio and transit pressure, in the estimation of bulk metal mass fraction. These differences between interior models entail a change in radius of up to 2.5% for Jupiter-mass planets, but more than 10\% for Neptune-mass. These are equivalent to variations in core mass fraction of 0.07, or 0.10 in envelope metal mass fraction.

arXiv comment18 pages, 9 figures. In review in Astronomy & Astrophysics

References in corpus (114)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• emcee: The MCMC Hammer
• Modules for Experiments in Stellar Astrophysics (MESA)
• Modules for Experiments in Stellar Astrophysics (MESA): Giant Planets, Oscillations, Rotation, and Massive Stars
• Modules for Experiments in Stellar Astrophysics (MESA): Binaries, Pulsations, and Explosions
• Modules for Experiments in Stellar Astrophysics (MESA): Convective Boundaries, Element Diffusion, and Massive Star Explosions
• Modules for Experiments in Stellar Astrophysics (MESA): Pulsating Variable Stars, Rotation, Convective Boundaries, and Energy Conservation
• Evolutionary models for cool brown dwarfs and extrasolar giant planets. The case of HD 20945
• A Non-Gray Theory of Extrasolar Giant Planets and Brown Dwarfs
• Planetary Radii across Five Orders of Magnitude in Mass and Stellar Insolation: Application to Transits
• The Theory of Brown Dwarfs and Extrasolar Giant Planets
• Kepler planets: a tale of evaporation
• Understanding the Mass-Radius Relation for Sub-Neptunes: Radius as a Proxy for Composition
• Atmospheric Circulation and Tides of "51Peg b-like" Planets
• Growth Model Interpretation of Planet Size Distribution
• On the radiative equilibrium of irradiated planetary atmospheres
• On the Luminosity of Young Jupiters
• The Mass-Metallicity Relation for Giant Planets
• Equatorial superrotation on tidally locked exoplanets
• Comparing Jupiter interior structure models to Juno gravity measurements and the role of a dilute core
• Spectral and Photometric Diagnostics of Giant Planet Formation Scenarios
• Planetary population synthesis coupled with atmospheric escape: a statistical view of evaporation
• Can we constrain interior structure of rocky exoplanets from mass and radius measurements?
• Is tidal heating sufficient to explain bloated exoplanets? Consistent calculations accounting for finite initial eccentricity
• The nature of the TRAPPIST-1 exoplanets
• Structure and evolution of super-Earth to super-Jupiter exoplanets: I. heavy element enrichment in the interior
• A Framework for Characterizing the Atmospheres of Low-Mass Low-Density Transiting Planets
• Inflating Hot Jupiters With Ohmic Dissipation
• Masses, Radii, and Cloud Properties of the HR 8799 Planets
• A new vision on giant planet interiors: the impact of double diffusive convection
• Ab initio Equation of State data for hydrogen, helium, and water and the internal structure of Jupiter
• Interior Models of Uranus and Neptune
• Model atmospheres of irradiated exoplanets: The influence of stellar parameters, metallicity, and the C/O ratio
• Evolutionary Analysis of Gaseous Sub-Neptune-Mass Planets with MESA
• Methane, Carbon Monoxide, and Ammonia in Brown Dwarfs and Self-Luminous Giant Planets
• HAT-P-26b: A Neptune-Mass Exoplanet with a Well Constrained Heavy Element Abundance
• On the Cool Side: Modeling the Atmospheres of Brown Dwarfs and Giant Planets
• Observing transiting planets with JWST -- Prime targets and their synthetic spectral observations
• Bayesian Analysis of Hot Jupiter Radius Anomalies: Evidence for Ohmic Dissipation?
• Quenching of Carbon Monoxide and Methane in the Atmospheres of Cool Brown Dwarfs and Hot Jupiters
• A new equation of state for dense hydrogen-helium mixtures
• Phase Separation in Giant Planets: Inhomogeneous Evolution of Saturn
• A Systematic Study of Departures from Chemical Equilibrium in the Atmospheres of Substellar Mass Objects
• AQUA: A Collection of H${}_2$O Equations of State for Planetary Models
• The water abundance in Jupiter's equatorial zone
• Advection of potential temperature in the atmosphere of irradiated exoplanets: a robust mechanism to explain radius inflation
• Ohmic Dissipation in the Atmospheres of Hot Jupiters
• HAT-P-26b: A Low-Density Neptune-Mass Planet Transiting a K Star
• The interior and atmosphere of the habitable-zone exoplanet K2-18b
• Beyond Equilibrium Temperature: How the Atmosphere/Interior Connection Affects the Onset of Methane, Ammonia, and Clouds in Warm Transiting Giant Planets
• Irradiated ocean planets bridge super-Earth and sub-Neptune populations
• Jupiter's evolution with primordial composition gradients
• Mass-radius relationships for irradiated ocean planets
• A High Internal Heat Flux and Large Core in a Warm Neptune Exoplanet
• Effects of Helium Phase Separation on the Evolution of Extrasolar Giant Planets
• The fuzziness of giant planets' cores
• Conclusive evidence for a population of water-worlds around M-dwarfs remains elusive
• A warm Neptune's methane reveals core mass and vigorous atmospheric mixing
• Jupiter's inhomogeneous envelope
• A new equation of state for dense hydrogen-helium mixtures II: taking into account hydrogen-helium interactions
• A Search for Water in the Atmosphere of HAT-P-26b Using LDSS-3C
• Jupiter's formation and its primordial internal structure
• Toward the analysis of JWST exoplanet spectra: Identifying troublesome model parameters
• Constraints on Super-Earths Interiors from Stellar Abundances
• Ab initio based equation of state of dense water for planetary and exoplanetary modeling
• Evidence of Three Mechanisms Explaining the Radius Anomaly of Hot Jupiters
• Idealised simulations of the deep atmosphere of hot jupiters: Deep, hot, adiabats as a robust solution to the radius inflation problem
• Tidal Heating Models for the Radii of the Inflated Transiting Giant Planets WASP-4b, WASP-6b, WASP-12b, and TrES-4
• A new perspective on interiors of ice-rich planets: Ice-rock mixture instead of ice on top of rock
• The puzzling chemical composition of GJ 436b's atmosphere: influence of tidal heating on the chemistry
• Convection and Mixing in Giant Planet Evolution
• Models of Saturn's Interior Constructed with Accelerated Concentric Maclaurin Spheroid Method
• Evidence for a Dichotomy in the Interior Structures of Jupiter and Saturn from Helium Phase Separation
• Jupiter's interior from Juno: Equation-of-state uncertainties and dilute core extent
• Characterisation of the hydrospheres of TRAPPIST-1 planets
• Effect of Non-Adiabatic Thermal Profiles on the Inferred Compositions of Uranus and Neptune
• Prospects for Detection of Extra-Solar Giant Planets by Next-Generation Telescopes
• The Metal-Rich Atmosphere of the Neptune HAT-P-26b
• Dynamical Constraints on the Core Mass of Hot Jupiter HAT-P-13b
• Do Metal-Rich Stars Make Metal-Rich Planets? New Insights on Giant Planet Formation from Host Star Abundances
• Planet formation around M dwarfs via disc instability: Fragmentation conditions and protoplanet properties
• On the degeneracy of the tidal Love number k2 in multi-layer planetary models: application to Saturn and GJ436b
• Detection of the tidal deformation of WASP-103b at $3\sigma$ with CHEOPS
• Impact of the measured parameters of exoplanets on the inferred internal structure
• Explorations into the Viability of Coupled Radius-Orbit Evolutionary Models for Inflated Planets
• ExoMDN: Rapid characterization of exoplanet interior structures with Mixture Density Networks
• Latitudinal variation in the abundance of methane (CH4) above the clouds in Neptune's atmosphere from VLT/MUSE Narrow Field Mode Observations
• On the mass of gas giant planets: Is Saturn a failed gas giant?
• An estimate of the $k_2$ Love number of WASP-18Ab from its radial velocity measurements
• THOR 2.0: Major Improvements to the Open-Source General Circulation Model
• Possible Internal Structures and Compositions of Proxima Centauri b
• Accounting for non-ideal mixing effects in the hydrogen-helium equation of state
• Synthetic Evolution Tracks of Giant Planets
• Nitrogen as a Tracer of Giant Planet Formation. I.: A Universal Deep Adiabatic Profile and Semi-analytical Predictions of Disequilibrium Ammonia Abundances in Warm Exoplanetary Atmospheres
• MAGRATHEA: an open-source spherical symmetric planet interior structure code
• A subsolar oxygen abundance or a radiative region deep in Jupiter revealed by thermochemical modelling
• Towards a new era in giant exoplanet characterisation
• The Effect of Clouds as an Additional Opacity Source on the Inferred Metallicity of Giant Exoplanets
• Exoplanet Interior Retrievals: core masses and metallicities from atmospheric abundances
• Super-adiabatic Temperature Gradient at Jupiter's Equatorial Zone and Implications for the Water Abundance
• The Atmosphere and Interior Structure of HAT-P-13b from Spitzer Secondary Eclipses
• No evidence for radius inflation in hot Jupiters from vertical advection of heat
• Latitudinal variation of methane mole fraction above clouds in Neptune's atmosphere from VLT/MUSE-NFM: Limb-darkening reanalysis
• The effect of interior heat flux on the atmospheric circulation of hot and ultra-hot Jupiters
• A new method to measure the spectra of transiting exoplanet atmospheres using multi-object spectroscopy
• Water content trends in K2-138 and other low-mass multiplanetary systems
• On the Effects of Planetary Oblateness on Exoplanet Studies
• Interior-atmosphere modelling to assess the observability of rocky planets with JWST
• HST/STIS capability for Love number measurement of WASP-121b
• Evidence of apsidal motion and a possible co-moving companion star detected in the WASP-19 system
• Connecting gravity field, moment of inertia, and core properties in Jupiter through empirical structure models
• The effect of cloudy atmospheres on the thermal evolution of warm giant planets from an interior modelling perspective
• Constraining the oblateness of transiting planets with photometry and spectroscopy
• Possible formation pathways for the low density Neptune-mass planet HAT-P-26b

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• TOI-5005 b: A super-Neptune in the savanna near the ridge
• Unraveling the origin of giant exoplanets: Observational implications of convective mixing
• Three Warm Jupiters orbiting TOI-6628, TOI-3837, TOI-5027 and one sub-Saturn orbiting TOI-2328
• GEMS JWST: Transmission spectroscopy of TOI-5205b reveals significant stellar contamination and a metal-poor atmosphere
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• Evidence of a gap in the envelope mass fraction of sub-Saturns
• A Warm Massive Pair of Planets around TOI-1232 Revealed with Transit-timing Variations and Doppler Spectroscopy
• TOI-1438: A rare system with two short-period sub-Neptunes and a tentative long-period Jupiter-like planet orbiting a K0V star