Retrieval of Exoplanet Emission Spectra with HyDRA

Abstract

Thermal emission spectra of exoplanets provide constraints on the chemical compositions, pressure-temperature (P-T) profiles, and energy transport in exoplanetary atmospheres. Accurate inferences of these properties rely on the robustness of the atmospheric retrieval methods employed. While extant retrieval codes have provided significant constraints on molecular abundances and temperature profiles in several exoplanetary atmospheres, the constraints on their deviations from thermal and chemical equilibria have yet to be fully explored. Our present work is a step in this direction. We report HyDRA, a disequilibrium retrieval framework for thermal emission spectra of exoplanetary atmospheres. The retrieval code uses the standard architecture of a parametric atmospheric model coupled with Bayesian statistical inference using the Nested Sampling algorithm. For a given dataset, the retrieved compositions and P-T profiles are used in tandem with the GENESIS self-consistent atmospheric model to constrain layer-by-layer deviations from chemical and radiative-convective equilibrium in the observable atmosphere. We demonstrate HyDRA on the Hot Jupiter WASP-43b with a high-precision emission spectrum. We retrieve an H2O mixing ratio of log(H2O) = -3.54^{+0.82}_{-0.52}, consistent with previous studies. We detect H2O and a combined CO/CO2 at 8-sigma significance. We find the dayside P-T profile to be consistent with radiative-convective equilibrium within the 1-sigma limits and with low day-night redistribution, consistent with previous studies. The derived compositions are also consistent with thermochemical equilibrium for the corresponding distribution of P-T profiles. In the era of high precision and high resolution emission spectroscopy, HyDRA provides a path to retrieve disequilibrium phenomena in exoplanetary atmospheres.

20 pages, 13 figures, Accepted for publication in MNRAS

References in corpus (16)

• Bayes in the sky: Bayesian inference and model selection in cosmology
• On the radiative equilibrium of irradiated planetary atmospheres
• A Precise Water Abundance Measurement for the Hot Jupiter WASP-43b
• Detection of Carbon Monoxide and Water Absorption Lines in an Exoplanet Atmosphere
• Possible thermochemical disequilibrium in the atmosphere of the exoplanet GJ 436b
• Theoretical Spectra and Light Curves of Close-in Extrasolar Giant Planets and Comparison with Data
• Towards Chemical Constraints on Hot Jupiter Migration
• An ultrahot gas-giant exoplanet with a stratosphere
• Spitzer Phase Curve Constraints for WASP-43b at 3.6 and 4.5 microns
• The Atmospheric Circulation of the Hot Jupiter WASP-43b: Comparing Three-Dimensional Models to Spectrophotometric Data
• H2O abundances in the atmospheres of three hot Jupiters
• New Analysis Indicates No Thermal Inversion in the Atmosphere of HD 209458b
• GENESIS: New Self-Consistent Models of Exoplanetary Spectra
• Deciphering the Atmospheric Composition of WASP-12b: A Comprehensive Analysis of its Dayside Emission
• Retrieval Analysis of the Emission Spectrum of WASP-12b: Sensitivity of Outcomes to Prior Assumptions and Implications for Formation History
• Atmospheric Compositions of Three Brown Dwarfs and Implications for their Formation Conditions

Cited by in corpus (42)

• Mass-Metallicity Trends in Transiting Exoplanets from Atmospheric Abundances of H${}_2$O, Na, and K
• The 2020 release of the ExoMol database: molecular line lists for exoplanet and other hot atmospheres
• Retrieving scattering clouds and disequilibrium chemistry in the atmosphere of HR 8799e
• A reflective, metal-rich atmosphere for GJ 1214b from its JWST phase curve
• A broadband thermal emission spectrum of the ultra-hot Jupiter WASP-18b
• Atmospheric Regimes and Trends on Exoplanets and Brown Dwarfs
• Connecting planet formation and astrochemistry: A main sequence for C/O in hot-exoplanetary atmospheres
• Molecular Cross Sections for High Resolution Spectroscopy of Super Earths, Warm Neptunes and Hot Jupiters
• Sparkling nights and very hot days on WASP-18b: the formation of clouds and the emergence of an ionosphere
• Near-Infrared Transmission Spectroscopy of HAT-P-18b with NIRISS: Disentangling Planetary and Stellar Features in the Era of JWST
• HyDRA-H: Simultaneous Hybrid Retrieval of Exoplanetary Emission Spectra
• Spatially-resolving the terminator: Variation of Fe, temperature and winds in WASP-76 b across planetary limbs and orbital phase
• Awesome SOSS: Atmospheric Characterisation of WASP-96 b using the JWST Early Release Observations
• A comparison of chemical models of exoplanet atmospheres enabled by TauREx 3.1
• On Atmospheric Retrievals of Exoplanets with Inhomogeneous Terminators
• Neural posterior estimation for exoplanetary atmospheric retrieval
• Assessment of Supervised Machine Learning for Atmospheric Retrieval of Exoplanets
• Exoplanet atmosphere retrievals in 3D using phase curve data with ARCiS: application to WASP-43b
• The carbon-to-oxygen ratio: implications for the spectra of hydrogen-dominated exoplanet atmospheres
• Aluminium oxide in the atmosphere of hot Jupiter WASP-43b
• Considerations for Atmospheric Retrieval of High-Precision Brown Dwarf Spectra
• Aura-3D: A Three-dimensional Atmospheric Retrieval Framework for Exoplanet Transmission Spectra
• Retrieval study of cool, directly imaged exoplanet 51 Eri b
• Revisiting the atmosphere of the exoplanet 51 Eridani b with VLT/SPHERE
• A Catalogue of Exoplanet Atmospheric Retrieval Codes
• Ground-Based Transmission Spectroscopy with FORS2: A featureless optical transmission spectrum and detection of H${}_2$O for the ultra-hot Jupiter WASP-103b
• H- and Dissociation in Ultra-hot Jupiters: A Retrieval Case Study of WASP-18b
• The PHOENIX Exoplanet Retrieval Algorithm and Using H${}^{-}$ Opacity as a Probe in Ultra-hot Jupiters
• Data availability and requirements relevant for the Ariel space mission and other exoplanet atmosphere applications
• TauREx3 PhaseCurve: A 1.5D model for phase curve description
• Ions in the Thermosphere of Exoplanets: Observable Constraints Revealed by Innovative Laboratory Experiments
• A retrieval challenge exercise for the Ariel mission
• YunMa: Enabling Spectral Retrievals of Exoplanetary Clouds
• Toward a multidimensional analysis of transmission spectroscopy. Part III: Modelling 2D effects in retrievals with TauREx
• Another look at the dayside spectra of WASP-43b and HD 209458b: are there scattering clouds?
• LRG-BEASTS: Evidence for clouds in the transmission spectrum of HATS-46 b
• The curse of clouds
• CROCODILE \\ Incorporating medium-resolution spectroscopy of close-in directly imaged exoplanets into atmospheric retrievals via cross-correlation
• Horizontal and vertical exoplanet thermal structure from a JWST spectroscopic eclipse map
• Radiative Transfer and Inversion codes for characterizing planetary atmospheres: an overview
• Magnetic Drag and 3-D Effects in Theoretical High-Resolution Emission Spectra of Ultrahot Jupiters: the Case of WASP-76b
• HyDRo: Atmospheric Retrieval of Rocky Exoplanets in Thermal Emission