Integrating light-curve and atmospheric modelling of transiting exoplanets

Abstract

Spectral retrieval techniques are currently our best tool to interpret the observed exoplanet atmospheric data. Said techniques retrieve the optimal atmospheric components and parameters by identifying the best fit to an observed transmission/emission spectrum. Over the past decade, our understanding of remote worlds in our galaxy has flourished thanks to the use of increasingly sophisticated spectral retrieval techniques and the collective effort of the community working on exoplanet atmospheric models. A new generation of instruments in space and from the ground is expected to deliver higher quality data in the next decade, it is therefore paramount to upgrade current models and improve their reliability, completeness and numerical speed with which they can be run. In this paper, we address the issue of reliability of the results provided by retrieval models in the presence of systematics of unknown origin. More specifically, we demonstrate that if we fit directly individual light-curves at different wavelengths (L-retrieval), instead of fitting transit or eclipse depths, as it is currently done (S-retrieval), the results obtained are more robust against astrophysical and instrumental noise. This new approach is tested, in particular, when discrepant simulated observations from HST/WFC3 and Spitzer/IRAC are combined. We find that while S-retrievals converge to an incorrect solution without any warning, L-retrievals are able to identify potential discrepancies between the data-sets.

14 pages, 15 figures,Submitted to ApJ

References in corpus (22)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• Sodium Absorption From the Exoplanetary Atmosphere of HD189733b Detected in the Optical Transmission Spectrum
• A Precise Water Abundance Measurement for the Hot Jupiter WASP-43b
• Helium in the eroding atmosphere of an exoplanet
• H- Opacity and Water Dissociation in the Dayside Atmosphere of the Very Hot Gas Giant WASP-18 b
• Tau-REx I: A next generation retrieval code for exoplanetary atmospheres
• Water vapour in the atmosphere of the habitable-zone eight Earth-mass planet K2-18 b
• Markov Chain Monte Carlo Methods for Bayesian Data Analysis in Astronomy
• Simultaneous Detection of Water, Methane and Carbon Monoxide in the Atmosphere of Exoplanet HR8799b
• The 4.5 $\mu$m full-orbit phase curve of the hot Jupiter HD 209458b
• New Analysis Indicates No Thermal Inversion in the Atmosphere of HD 209458b
• A library of ATMO forward model transmission spectra for hot Jupiter exoplanets
• Deciphering the Atmospheric Composition of WASP-12b: A Comprehensive Analysis of its Dayside Emission
• Retrieval of Exoplanet Emission Spectra with HyDRA
• On the Presence of Water and Global Circulation in the Transiting Planet HD 189733b
• Exoplanet Spectroscopy and Photometry with the Twinkle Space Telescope
• The ExoTETHyS package: Tools for Exoplanetary Transits around Host Stars
• Near-infrared transmission spectrum of the warm-uranus GJ 3470b with the Wide Field Camera-3 on the Hubble Space Telescope
• Magnetised winds and their influence in the escaping upper atmosphere of HD 209458b
• Signatures of Nitrogen Chemistry in Hot Jupiter Atmospheres
• Characterization of Exoplanet Atmospheres with the Optical Coronagraph on WFIRST

Cited by in corpus (15)

• TauREx III: A fast, dynamic and extendable framework for retrievals
• Five key exoplanet questions answered via the analysis of 25 hot Jupiter atmospheres in eclipse
• Hubble WFC3 Spectroscopy of the Habitable-zone Super-Earth LHS 1140 b
• ARES V: No Evidence For Molecular Absorption in the HST WFC3 Spectrum of GJ 1132 b
• On The Compatibility of Ground-based and Space-based Data: WASP-96 b, An Example
• Is the atmosphere of the ultra-hot Jupiter WASP-121b variable?
• KELT-11 b: Abundances of water and constraints on carbon-bearing molecules from the Hubble transmission spectrum
• An exploration of model degeneracies with a unified phase curve retrieval analysis: The light and dark sides of WASP-43 b
• Clouds form on the hot Saturn JWST ERO target WASP-96b
• WASP-117 b: an eccentric hot-Saturn as a future complex chemistry laboratory
• Hot exoplanetary atmospheres in 3D
• Terminus: A Versatile Simulator for Space-based Telescopes
• Comparing transit spectroscopy pipelines at the catalogue level: evidence for systematic differences
• Lessons from Hubble and Spitzer: 1D Self-Consistent Model Grids for 19 Hot Jupiter Emission Spectra
• Exploring Synergies between Twinkle and Ariel: a Pilot Study