Exoplanet atmospheres

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Reanalyzing Jupiter ISO/SWS Data through a More Recent Atmospheric Model

ATMOSPHERE 14:12 (2023) ARTN 1731

Authors:

Jose Ribeiro, Pedro Machado, Santiago Perez-Hoyos, Joao A Dias, Patrick Irwin, Elizabeth A Silber, George Balasis

Abstract:

The study of isotopic ratios in planetary atmospheres gives an insight into the formation history and evolution of these objects. The more we can constrain these ratios, the better we can understand the history and future of our solar system. To help in this endeavour, we used Infrared Space Observatory Short Wavelength Spectrometer (ISO/SWS) Jupiter observations in the 793–1500 cm (Formula presented.) region together with the Nonlinear Optimal Estimator for MultivariatE Spectral analySIS (NEMESIS) radiative transfer suite to retrieve the temperature–pressure profile and the chemical abundances for various chemical species. We also used the 1500–2499 cm (Formula presented.) region to determine the cloud and aerosol structure of the upper troposphere. We obtained a best-fit simulated spectrum with (Formula presented.) for the 793–1500 cm (Formula presented.) region and (Formula presented.) for the 1500–2499 cm (Formula presented.) region. From the retrieved methane abundances, we obtained, within a 1 (Formula presented.) uncertainty, a (Formula presented.) C/ (Formula presented.) C ratio of 84 ± 27 and a D/H ratio of (3.5 ± 0.6) × 10 (Formula presented.), and these ratios are consistent with other published results from the literature.
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An intense narrow equatorial jet in Jupiter's lower stratosphere observed by JWST

NATURE ASTRONOMY (2023)

Authors:

Ricardo Hueso, Agustin Sanchez-Lavega, Thierry Fouchet, Imke de Pater, Arrate Antunano, Leigh N Fletcher, Michael H Wong, Pablo Rodriguez-Ovalle, Lawrence A Sromovsky, Patrick M Fry, Glenn S Orton, Sandrine Guerlet, Patrick GJ Irwin, Emmanuel Lellouch, Jake Harkett, Katherine de Kleer, Henrik Melin, Vincent Hue, Amy A Simon, Statia Luszcz-Cook, Kunio M Sayanagi
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Testing 2D temperature models in Bayesian retrievals of atmospheric properties from hot Jupiter phase curves

Monthly notices of the Royal Astronomical Society

Authors:

Jingxuan Yang, Patrick G.J. Irwin, Joanna K. Barstow

Abstract:

Spectroscopic phase curves of transiting hot Jupiters are spectral measurements at multiple orbital phases, giving a set of disc-averaged spectra that probe multiple hemispheres. By fitting model phase curves to observations, we can constrain the atmospheric properties of hot Jupiters such as molecular abundance, aerosol distribution and thermal structure, which offer insights into their dynamics, chemistry, and formation. In this work, we propose a novel 2D temperature scheme consisting of a dayside and a nightside to retrieve information from near-infrared phase curves, and apply the scheme to phase curves of WASP-43b observed by HST/WFC3 and Spitzer/IRAC. In our scheme, temperature is constant on isobars on the nightside and varies with cos^n(longitude/ϵ) on isobars on the dayside, where n and ϵ are free parameters. We fit all orbital phases simultaneously using the radiative transfer package NEMESISPY coupled to a Bayesian inference code. We first validate the performance of our retrieval scheme with synthetic phase curves generated from a GCM, and find our 2D scheme can accurately retrieve the latitudinally-averaged thermal structure and constrain the abundance of H2O and CH4. We then apply our 2D scheme to the observed phase curves of WASP-43b and find: (1) the dayside temperature-pressure profiles do not vary strongly with longitude and are non-inverted; (2) the retrieved nightside temperatures are extremely low, suggesting significant nightside cloud coverage; (3) the H2O volume mixing ratio is constrained to 5.6×10^−5--4.0×10^−4, and we retrieve an upper bound for CH4 at ∼10^−6.
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Detecting life outside our solar system with a large high-contrast-imaging mission

Experimental Astronomy Springer Nature 54:2-3 (2022) 1237-1274

Authors:

Ignas AG Snellen, F Snik, M Kenworthy, S Albrecht, G Anglada-Escudé, I Baraffe, P Baudoz, W Benz, J-L Beuzit, B Biller, JL Birkby, A Boccaletti, R van Boekel, J de Boer, Matteo Brogi, L Buchhave, L Carone, M Claire, R Claudi, B-O Demory, J-M Désert, S Desidera, BS Gaudi, R Gratton, M Gillon, JL Grenfell, O Guyon, T Henning, S Hinkley, E Huby, M Janson, C Helling, K Heng, M Kasper, CU Keller, O Krause, L Kreidberg, N Madhusudhan, A-M Lagrange, R Launhardt, TM Lenton, M Lopez-Puertas, A-L Maire, N Mayne, V Meadows, B Mennesson, G Micela, Y Miguel, J Milli, M Min, E de Mooij, D Mouillet, M N’Diaye, V D’Orazi, E Palle, I Pagano, G Piotto, D Queloz, H Rauer, I Ribas, G Ruane, F Selsis, A Sozzetti, D Stam, CC Stark, A Vigan, Pieter de Visser
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Seasonal changes in the vertical structure of ozone in the Martian lower atmosphere and its relationship to water vapor

Journal of Geophysical Research: Planets Wiley 127:10 (2022) e2022JE007213

Authors:

KS Olsen, AA Fedorova, A Trokhimovskiy, F Montmessin, F Lefèvre, O Korablev, L Baggio, F Forget, E Millour, A Bierjon, J Alday, CF Wilson, PGJ Irwin, DA Belyaev, A Patrakeev, A Shakun

Abstract:

The mid-infrared channel of the Atmospheric Chemistry Suite (ACS MIR) onboard the ExoMars Trace Gas Orbiter is capable of observing the infrared absorption of ozone (O3) in the atmosphere of Mars. During solar occulations, the 003←000 band (3,000-3,060 cm−1) is observed with spectral sampling of ∼0.045 cm−1. Around the equinoxes in both hemispheres and over the southern winters, we regularly observe around 200–500 ppbv of O3 below 30 km. The warm southern summers, near perihelion, produce enough atmospheric moisture that O3 is not detectable at all, and observations are rare even at high northern latitudes. During the northern summers, water vapor is restricted to below 10 km, and an O3 layer (100–300 ppbv) is visible between 20 and 30 km. At this same time, the aphelion cloud belt forms, condensing water vapor and allowing O3 to build up between 30 and 40 km. A comparison to vertical profiles of water vapor and temperature in each season reveals that water vapor abundance is controlled by atmospheric temperature, and H2O and O3 are anti-correlated as expected. When the atmosphere cools, over time or over altitude, water vapor condenses (observed as a reduction in its mixing ratio) and the production of odd hydrogen species is reduced, which allows O3 to build up. Conversely, warmer temperatures lead to water vapor enhancements and ozone loss. The LMD Mars Global Climate Model is able to reproduce vertical structure and seasonal changes of temperature, H2O, and O3 that we observe. However, the observed O3 abundance is larger by factors between 2 and 6, indicating important differences in the rate of odd-hydrogen photochemistry.
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