How Does Thermal Scattering Shape the Infrared Spectra of Cloudy Exoplanets? A Theoretical Framework and Consequences for Atmospheric Retrievals in the JWST era
arXiv:2009.12411 · doi:10.1093/mnras/stab1854
Abstract
Observational studies of exoplanets are suggestive of a ubiquitous presence of clouds. The current modelling techniques used in emission to account for the clouds tend to require prior knowledge of the cloud condensing species and often do not consider the scattering effects of the cloud. We explore the effects that thermal scattering has on the emission spectra by modelling a suite of hot Jupiter atmospheres with varying cloud single-scattering albedos (SSAs) and temperature profiles. We examine cases ranging from simple isothermal conditions to more complex structures and physically driven cloud modelling. We show that scattering from nightside clouds would lead to brightness temperatures that are cooler than the real atmospheric temperature if scattering is unaccounted for. We show that scattering can produce spectral signatures in the emission spectrum even for isothermal atmospheres. We identify the retrieval degeneracies and biases that arise in the context of simulated JWST spectra when the scattering from the clouds dominates the spectral shape. Finally, we propose a novel method of fitting the SSA spectrum of the cloud in emission retrievals, using a technique that does not require any prior knowledge of the cloud chemical or physical properties.
arXiv commentAccepted to MNRAS
References in corpus (63)
- Multimodal nested sampling: an efficient and robust alternative to MCMC methods for astronomical data analysis
- X-ray spectral modelling of the AGN obscuring region in the CDFS: Bayesian model selection and catalogue
- Importance Nested Sampling and the MultiNest Algorithm
- A continuum from clear to cloudy hot-Jupiter exoplanets without primordial water depletion
- Precipitating Condensation Clouds in Substellar Atmospheres
- ExoMol molecular line lists XXX: a complete high-accuracy line list for water
- Atmospheric circulation of hot Jupiters: Coupled radiative-dynamical general circulation model simulations of HD 189733b and HD 209458b
- Infrared Transmission Spectroscopy of the Exoplanets HD209458b and XO-1b Using the Wide Field Camera-3 on the Hubble Space Telescope
- A Precise Water Abundance Measurement for the Hot Jupiter WASP-43b
- Characterizing transiting exoplanet atmospheres with JWST
- A Systematic Retrieval Analysis of Secondary Eclipse Spectra I: A Comparison of Atmospheric Retrieval Techniques
- Atomic and Molecular Opacities for Brown Dwarf and Giant Planet Atmospheres
- From thermal dissociation to condensation in the atmospheres of ultra hot Jupiters: WASP-121b in context
- A population study of gaseous exoplanets
- Transitions in the cloud composition of hot Jupiters
- HD 209458b in New Light: Evidence of Nitrogen Chemistry, Patchy Clouds and Sub-Solar Water
- A Sub-Neptune Exoplanet with a Low-Metallicity Methane-Depleted Atmosphere and Mie-Scattering Clouds
- Model atmospheres of irradiated exoplanets: The influence of stellar parameters, metallicity, and the C/O ratio
- Aerosol Composition of Hot Giant Exoplanets Dominated by Silicates and Hydrocarbon Hazes
- Transmission spectral properties of clouds for hot Jupiter exoplanets
- Spitzer Infrared Spectrograph Observations of M, L, and T Dwarfs
- The Influence of Non-Uniform Cloud Cover on Transit Transmission Spectra
- HO abundances and cloud properties in ten hot giant exoplanets
- The TRAPPIST survey of southern transiting planets. I. Thirty eclipses of the ultra-short period planet WASP-43 b
- A consistent retrieval analysis of 10 Hot Jupiters observed in transmission
- Spitzer Phase Curve Constraints for WASP-43b at 3.6 and 4.5 microns
- Dust in Brown Dwarfs and Extra-solar Planets I. Chemical composition and spectral appearance of quasi-static cloud layers
- WASP-43b: The closest-orbiting hot Jupiter
- No Thermal Inversion and a Solar Water Abundance for the Hot Jupiter HD209458b from HST WFC3 Emission Spectroscopy
- The ExoMolOP Database: Cross-sections and k-tables for Molecules of Interest in High-Temperature Exoplanet Atmospheres
- The Atmospheric Circulation of the Hot Jupiter WASP-43b: Comparing Three-Dimensional Models to Spectrophotometric Data
- HELIOS-Retrieval: An Open-source, Nested Sampling Atmospheric Retrieval Code, Application to the HR 8799 Exoplanets and Inferred Constraints for Planet Formation
- Retrieval analysis of 38 WFC3 transmission spectra and resolution of the normalisation degeneracy
- A non-grey analytical model for irradiated atmospheres. I: Derivation
- Retrieval of atmospheric properties of cloudy L dwarfs
- Treatment of overlapping gaseous absorption with the correlated-k method in hot Jupiter and brown dwarf atmosphere models
- The cloudy shape of hot Jupiter thermal phase curves
- The Transiting Exoplanet Community Early Release Science Program for JWST
- Formation of Silicate and Titanium Clouds on Hot Jupiters
- Characterizing Earth Analogs in Reflected Light: Atmospheric Retrieval Studies for Future Space Telescopes
- Atmospheric Retrieval Analysis of the Directly Imaged Exoplanet HR 8799b
- Transiting Exoplanet Studies and Community Targets for JWST's Early Release Science Program
- Spitzer Phase Curves of KELT-1b and the Signatures of Nightside Clouds in Thermal Phase Observations
- On degeneracies in retrievals of exoplanetary transmission spectra
- On Signatures of Clouds in Exoplanetary Transit Spectra
- Understanding and Mitigating Biases when Studying Inhomogeneous Emission Spectra with JWST
- Clouds on the hot Jupiter HD189733b: constraints from the reflection spectrum
- Uniformly hot nightside temperatures on short-period gas giants
- 2.5-D retrieval of atmospheric properties from exoplanet phase curves: Application to WASP-43b observations
- A Characteristic Transmission Spectrum dominated by HO applies to the majority of HST/WFC3 exoplanet observations
- Towards a more complex description of chemical profiles in exoplanets retrievals: A 2-layer parameterisation
- Unveiling cloudy exoplanets: the influence of cloud model choices on retrieval solutions
- Sparkling nights and very hot days on WASP-18b: the formation of clouds and the emergence of an ionosphere
- Exploring Exoplanet Cloud Assumptions in \textit{JWST} Transmission Spectra
- Microphysical Modeling of Mineral Clouds in GJ1214 b and GJ436 b: Predicting Upper Limits on the Cloud-Top Height
- HST PanCET program: A Cloudy Atmosphere for the promising JWST target WASP-101b
- Detection of Na, K and HO in the hazy atmosphere of WASP-6b
- Exoplanet Atmosphere Forecast: Observers Should Expect Spectroscopic Transmission Features to be Muted to 33%
- Colour and Tropospheric Cloud Structure of Jupiter from MUSE/VLT: Retrieving a Universal Chromophore
- Mineral snowflakes on exoplanets and brown dwarfs: Effects of micro-porosity, size distributions, and particle shape
- The influence of non-isotropic scattering of thermal radiation on spectra of brown dwarfs and hot exoplanets
- Reanalysis of Uranus' cloud scattering properties from IRTF/SpeX observations using a self-consistent scattering cloud retrieval scheme
- Global Chemistry and Thermal Structure Models for the Hot Jupiter WASP-43b and Predictions for JWST
Cited by in corpus (16)
- PICASO 3.0: A One-Dimensional Climate Model for Giant Planets and Brown Dwarfs
- Aerosols in Exoplanet Atmospheres
- A unique hot Jupiter spectral sequence with evidence for compositional diversity
- The Roasting Marshmallows Program with IGRINS on Gemini South I: Composition and Climate of the Ultra Hot Jupiter WASP-18 b
- 3D radiative-transfer for exoplanet atmospheres. gCMCRT: a GPU accelerated MCRT code
- Multiple Clues for Dayside Aerosols and Temperature Gradients in WASP-69 b from a Panchromatic JWST Emission Spectrum
- Confirmation of Water Absorption in the Thermal Emission Spectrum of the Hot Jupiter WASP-77Ab with HST/WFC3
- A survey of exoplanet phase curves with Ariel
- Cloud Parameterizations and their Effect on Retrievals of Exoplanet Reflection Spectroscopy
- Emergent Spectral Fluxes of Hot Jupiters: an Abrupt Rise in Day Side Brightness Temperature Under Strong Irradiation
- In Search of the Edge: A Bayesian Exploration of the Detectability of Red Edges in Exoplanet Reflection Spectra
- JWST-TST DREAMS: Non-Uniform Dayside Emission for WASP-17b from MIRI/LRS
- Another look at the dayside spectra of WASP-43b and HD 209458b: are there scattering clouds?
- Cloudy solutions for the clear skies of WASP-80b: 3D cloud feedback on the atmosphere and spectra of a warm Jupiter
- Impact of Variable Photospheric Radius on Exoplanet Atmospheric Retrievals
- Grain Growth in Escaping Atmospheres: Implications for the Radius Inflation of Super-Puffs