Explanipedia

Optical constants of laboratory-generated analogs of the red chromophores in Jupiter’s atmosphere Open

Lora Jovanović, Ella Sciamma-O’Brien, Thomas Drant, Emma Dahl, Ashwin Braude , et al. · 2025

The identity of the coloring agent, or chromophore, in Jupiter’s atmosphere that causes the planet’s striking red clouds and storms is an area of active research. Despite being studied for more than 50 years across multiple observational m…

Sulfur allotropes and sulfur hydrides on the Venus cloud chemistry Open

Maxence Lefèvre, Franck Lefèvre, Anni Määttänen, Benjamin N. Frandsen, Robert Skog , et al. · 2025

. IntroductionThe cloud layer of Venus between 47 and 70 km is home to a vivid sulfur chemistry and microphysics, with SO2 as the major gas species and condensed phase composed of H2SO4 and H2O. This cloud layer has been extensively observ…

Joint Observations of Mesospheric Aerosols on Mars from MAVEN/IUVS and MRO/MCS Open

Ashwin Braude, M. Slipski, Sumedha Gupta, N. M. Schneider, A. Kleinboehl , et al. · 2025

JOINT OBSERVATIONS OF MESOSPHERIC AEROSOLS ON MARS FROM MAVEN/IUVS AND MRO/MCS Ashwin S. Braude1, Marek Slipski1, Sumedha Gupta2, Nicholas M. Schneider2, Armin Kleinböhl1, Franck Montmessin3, Sonal Jain2, Roger V. Yelle4 and Justin Deighan…

Modelling the Effect of the Sulphur Cycle on Episodic Climactic Changes on Early Mars Open

Ashwin Braude, L. Kerber, Franck Lefèvre, Yassin Jaziri, Saira Hamid , et al. · 2024

Introduction: Although Mars is now a cold, dry planet, the geological record shows that, early in its history, Mars not only went through episodes of wet-dry cycling [1], in which Mars could maintain liquid water on its surface for s…

Seasonal, Latitudinal, and Longitudinal Trends in Nighttime Ozone Vertical Structure on Mars From MAVEN/IUVS Stellar Occultations Open

Ashwin Braude, Franck Montmessin, N. M. Schneider, Sumedha Gupta, Sonal Jain , et al. · 2023

Stellar occultation measurements conducted by the Mars Atmosphere and Volatile and EvolutioN/Imaging UltraViolet Spectrograph instrument were able to make vertically resolved measurements of ozone density in the middle atmosphere of Mars t…

Pyrocast: a Machine Learning Pipeline to Forecast Pyrocumulonimbus (PyroCb) Clouds Open

Kenza Tazi, Emiliano Díaz Salas-Porras, Ashwin Braude, Daniel Okoh, Kara D. Lamb , et al. · 2022

Pyrocumulonimbus (pyroCb) clouds are storm clouds generated by extreme wildfires. PyroCbs are associated with unpredictable, and therefore dangerous, wildfire spread. They can also inject smoke particles and trace gases into the upper trop…

Identifying the Causes of Pyrocumulonimbus (PyroCb) Open

Emiliano Díaz Salas-Porras, Kenza Tazi, Ashwin Braude, Daniel Okoh, Kara D. Lamb , et al. · 2022

A first causal discovery analysis from observational data of pyroCb (storm clouds generated from extreme wildfires) is presented. Invariant Causal Prediction was used to develop tools to understand the causal drivers of pyroCb formation. T…

Measurements of HDO and the D/H ratio in the Martian atmosphere from ACS MIR Open

Ashwin Braude, Franck Montmessin, Kevin Olsen, Margaux Vals, Juan José Gómez Alday , et al. · 2022

Abstract Measuring vertical variations in the deuterium to hydrogen ratio with altitude is essential in understanding the processes that lead to the escape of water vapour from the M…

Modeling the Martian HDO cycle with a Global Climate Model during the “dusty” season Open

Margaux Vals, Franck Montmessin, Loïc Rossi, Ashwin Braude, Franck Lefèvre , et al. · 2022

Abstract The D/H ratio measured in the Martian atmosphere gives an estimation of the planet’s water escape rate. We present here a global circulation model including the wa…

Upper limits on volcanic gases in the Martian atmosphere from the ACS MIR instrument Open

Ashwin Braude, Franck Montmessin, Kevin Olsen, Аlexander Trokhimovskiy, Oleg Korablev , et al. · 2022

Abstract The geological record provides convincing evidence for very recent volcanic activity on Mars (e.g. Horvath et al. 2021, Icarus 365, 114499). In this talk we present the resu…

A Four-Year Search of Methane on Mars with ACS onboard ExoMars TGO Open

Franck Montmessin, Oleg Korablev, Аlexander Trokhimovskiy, Kevin Olsen, Franck Lefèvre , et al. · 2022

Summary The mid-infrared channel of the Atmospheric Chemistry Suite (ACS) [1] onboard ESA’s Trace Gas Orbiter (TGO) has performed a sensitive search of methane in the Marti…

Monitoring of Martian water ice clouds over one Martian Year with TGO/ACS-MIR Open

Aurélien Stcherbinine, Franck Montmessin, M. Vincendon, M. J. Wolff, Oleg Korablev , et al. · 2022

The Atmospheric Chemistry Suite (ACS) MIR channel onboard the ESA-Roscosmos Trace Gas Orbiter (TGO) (Korablev et al., 2018, 2019) probes the Martian atmosphere in the 2.3 – 4.2 µm spectral range using t…

Isotopic Composition of CO2 in the Atmosphere of Mars: Fractionation by Diffusive Separation Observed by the ExoMars Trace Gas Orbiter Open

Juan Alday, Colin Wilson, P. G. J. Irwin, Аlexander Trokhimovskiy, Franck Montmessin , et al. · 2021

Isotopic ratios in atmospheric CO 2 are shaped by various processes throughout Mars' history, and can help understand what the atmosphere of early Mars was like to sustain liquid water on its surface. In this study, we monitor the O and C …

No detection of SO2, H2S, or OCS in the atmosphere of Mars from the first two Martian years of observations from TGO/ACS Open

Ashwin Braude, Franck Montmessin, Kevin Olsen, Аlexander Trokhimovskiy, Oleg Korablev , et al. · 2021

The detection of sulphur species in the Martian atmosphere would be a strong indicator of volcanic outgassing from the surface of Mars. We wish to establish the presence of SO2, H2S, or OCS in the Martian atmosphere or determine upper limi…

No detection of SO2, H2S, or OCS in the atmosphere of Mars from the first two Martian years of observations from TGO/ACS Open

Ashwin Braude, Franck Montmessin, Kevin Olsen, Аlexander Trokhimovskiy, Oleg Korablev , et al. · 2021

Context. The detection of sulphur species in the Martian atmosphere would be a strong indicator of volcanic outgassing from the surface of Mars. Aims. We wish to establish the presence of SO 2 , H 2 S, or OCS in the Martian atmosphere or d…

The RISOTTO radiative transfer and retrieval pipeline for the analysis of occultation spectra Open

Ashwin Braude, S. Ferron, Franck Montmessin · 2021

International audience

Comparison of the HDO cycle in the LMD Mars GCM with ACS/TGO observations Open

Loïc Rossi, Margaux Vals, Franck Montmessin, Juan Alday, Ashwin Braude , et al. · 2021

HDO and the D/H ratio are important in order to understand Mars past and present climate, in particular regarding the evolution through ages of the Martian water cycle. We present simulations of the HDO cycle with the LMD Mars GCM and…

A stringent upper limit of 20 pptv for methane on Mars and constraints on its dispersion outside Gale crater Open

Franck Montmessin, Oleg Korablev, Аlexander Trokhimovskiy, Franck Lefèvre, Anna Fedorova , et al. · 2021

Context. Reports on the detection of methane in the Martian atmosphere have motivated numerous studies aiming to confirm or explain its presence on a planet where it might imply a biogenic or more likely a geophysical origin. Aims. Our int…

Upper limits for phosphine (PH3) in the atmosphere of Mars Open

Kevin Olsen, Аlexander Trokhimovskiy, Ashwin Braude, Oleg Korablev, Anna Fedorova , et al. · 2021

Phosphine (PH 3 ) is proposed to be a possible biomarker in planetary atmospheres and has been claimed to have been observed in the atmosphere of Venus, sparking interest in the habitability of Venus’s atmosphere. Observations of another b…

Color and aerosol changes in Jupiter after a North Temperate Belt disturbance Open

S. Pérez‐Hoyos, A. Sánchez‐Lavega, J. F. Sanz‐Requena, N. Barrado-Izagirre, Óscar Carrión-González , et al. · 2020

Colour and tropospheric cloud structure of Jupiter from MUSE/VLT: Retrieving a universal chromophore Open

Ashwin Braude, P. G. J. Irwin, Glenn S. Orton, Leigh N. Fletcher · 2019

Latitudinal variation in the abundance of methane (CH4) above the clouds in Neptune's atmosphere from VLT/MUSE Narrow Field Mode Observations Open

P. G. J. Irwin, Daniel Toledo, Ashwin Braude, Roland Bacon, Peter M. Weilbacher , et al. · 2019

Colour and cloud structure in the atmospheres of the giant planets Open

Ashwin Braude · 2019

For decades, the origin of colour-carrying compounds ('chromophores') in Jupiter and Saturn's atmospheres has remained elusive. Changes in colour are often associated with cyclical meteorological events ('upheavals') on Jupiter. Multiple d…

Analysis of gaseous ammonia (NH3) absorption in the visible spectrum of Jupiter Open

P. G. J. Irwin, Neil E. Bowles, Ashwin Braude, Ryan Garland, S. B. Calcutt · 2017

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