Planetary surfaces: publications

Corrigendum to “Isotope effects (Cl, O, C) of heterogeneous electrochemistry induced by Martian dust activities” [Earth and Planetary Science Letters 676 (2026) 119784]

Earth and Planetary Science Letters Elsevier 680 (2026) 119902

Authors:

Neil C Sturchio, Hao Yan, Alian Wang, W Andrew Jackson, Huiming Bao, Chuck YC Yan, Linnea J Heraty, Yu Wei, Quincy HK Qu, Kevin S Olsen

Comparative analysis of Venera 11, 13, and 14 spectrophotometric data: implications for the near-surface particulate layer

(2026)

Authors:

Shubham Kulkarni, Patrick Irwin, Colin Wilson, Nikolay Ignatie

Abstract:

The extreme conditions in Venus’s lower atmosphere make robust calibration of in situ observations challenging. Consequently, measurements from past entry probes provided mixed evidence regarding the existence of a near-surface particulate layer (NSPL). Although the Venera 11 (1978) and Venera 13 and 14 (1982) landers performed in situ spectrophotometric observations during descent, the original datasets were later lost. However, a subset has been reconstructed by digitising graphical outputs produced during the missions’ initial data-processing phase [1]. Following careful analysis to identify and mitigate errors and other artefacts, the reconstructed dataset retains the reliable downward-looking spectra acquired by the three landers from ~62 km altitude to the surface.Previous retrievals from the reconstructed Venera 13 indicated an NSPL centred at ~3.5–5 km, with particulate optical properties consistent with a basaltic composition [2]. Following the methodology of [2], we use NEMESIS, a radiative transfer and retrieval code [3], to perform near-surface retrievals from the reconstructed Venera 11 and Venera 14 datasets. The results from Venera 11, 13, and 14 retrievals are compared with reported detections and non-detections from other instruments on earlier in situ missions, to explore potential formation pathways for the NSPL in light of the combined observational record.References:[1] Ignatiev, N. I., Moroz, V. I., Moshkin, B. E., Ekonomov, A. P., Gnedykh, V. I., Grigor’ev, A. V., and Khatuntsev, I. V. Cosmic Research 35(1), 1–14 (1997).[2] Kulkarni, S. V., Irwin, P. G. J., Wilson, C. F., & Ignatiev, N. I. Journal of Geophysical Research: Planets, 130, e2024JE008728, (2025).[3] Irwin, P. G., Teanby, N. A., de Kok, R., Fletcher, L. N., Howett, C. J., Tsang, C. C., Wilson, C. F., Calcutt, S. B., Nixon, C. A., and Parrish, P. D. Journal of Quantitative Spectroscopy and Radiative Transfer 109(6), 1136–1150 (2008).

Modelling the Variation of HCl in the Martian Atmosphere

(2026)

Authors:

Bethan Gregory, Kevin Olsen, Ehouarn Millour, Megan Brown, Paul Streeter, Kylash Rajendran, Manish Patel

Abstract:

The ExoMars Trace Gas Orbiter (TGO) has characterised trace gases in the Martian atmosphere over several Mars years, improving the accuracy of species concentration measurements and observing temporal, vertical and spatial variations. Hydrogen chloride—detected for the first time with TGO [1,2]—has been investigated recently using the mid-infrared channel on the Atmospheric Chemistry Suite (ACS MIR). HCl observations show a strong seasonal variation, with almost all of the detections occurring during the latter half of the year (solar longitudes 180-360°) in the dusty season, when water vapour is present in the Martian atmosphere and ozone concentrations are low. Chlorine-bearing species such as HCl are important to understand in Mars’ atmosphere because on Earth they are involved in numerous processes throughout the planetary system, including volcanism, and they play a key role in atmospheric chemistry, e.g., by influencing concentrations of oxidative species such as oxygen (O2) and ozone (O3).Here, we use the Mars Planetary Climate Model—a 3-D global climate model that includes a photochemical network—to explore the atmospheric HCl observations. We build on existing chlorine photochemical networks [3,4] to investigate potential source and sink mechanisms, focusing in particular on heterogeneous chemistry involving ice aerosols, and exploring the possibility of its role in direct release of HCl to the atmosphere. We also explore how chlorine species are affected indirectly by changes in the abundances of oxidative species (e.g., OH and HO2,and by extension, O and O3),driven by heterogeneous chemistry. Understanding the role of oxidative chemistry on HCl and other trace gases is key to achieving a more complete picture of processes occurring in the present-day Mars atmosphere, as well as processes that have shaped its evolution and habitability.[1] Korablev O. I. et al. (2021). Sci. Adv., 7, eabe4386. [2] Olsen K. S. et al. (2021). Astron. Astrophys., 647, A161. [3] Rajendran, K. et al. (2025). JGR: Planets 130(3), p.e2024JE008537. [4] Streeter, P. M. et al. (2025). GRL 52(6), p.e2024GL111059.

PANDOR-I: Preliminary vacuum chamber experimental set-up of dust layering, ice-regolith lunar analogues in reflectance (1.8 – 20 µm)

(2026)

Authors:

Fiona Henderson, Neil Bowles, Katherine Shirley, Namrah Habib, Henry Eshbaugh

Abstract:

Hydration on the Moon’s surface is widely detected in orbital datasets (e.g. M3 on Chandrayan-1), yet its abundance and physical form (-OH, H2O, frost, and/or ice) remain poorly constrained. The lunar surface is covered in regolith fines, which impacts local thermophysical conditions, obscures underlying volatiles and modifies detectable hydration bands. Our interpretation of hydration form and abundance on the lunar surface is further limited by existing experimental constraints of water-ice spectral behaviour at the regolith interface (photometric effects) and by the restriction of current orbital datasets to the near-infrared (< ~3 µm O–H stretching mode). We are developing a laboratory approach to quantify how dust layering, regolith maturity, grain size, composition, and ice abundance control the spectral expression of water-ice across the near- and mid-infrared (1.8–20 µm), with emphasis on the ~3 and 6 µm diagnostic regions. This poster presents a preliminary experimental set-up developed ahead of the full operation of a custom-built vacuum chamber, Polar Analogue of Dust Overlying Regolith–Ice (PANDOR-I), intended to simulate airless-body and cryogenic polar conditions. In this initial laboratory set-up, the sample compartment of a Bruker 70V Fourier Transform Infrared (FTIR) spectrometer is isolated using potassium bromide (KBr) windows to enable controlled, low-pressure (~0.2 mbar) reflectance measurements of anhydrous and hydrated analogue configurations to (i) characterise the spectral expression of hydration-related structure in the ~3 and 6 µm regions under regolith simulant fines, and (ii) provide benchmark spectra for direct comparison with a Mie–Hapke forward model (band shape,depth, and mixing trends) prior to cryogenic and airless body simulations with PANDOR-I. This preliminary work will establish an empirical reference for model validation and for designing the subsequent PANDOR-I cryogenic experiments, enabling a more robust interpretation of spectrally mixed hydration signatures in forthcoming lunar datasets.

The Key to Unlocking Exoplanet Biosignatures: a UK-led IR Spectrograph for the Habitable Worlds Observatory Coronagraph

(2026)

Authors:

Beth Biller, Dan Dicken, Olivier Absil, Raziye Artan, Jo Barstow, Jayne Birkby, Christophe Dumas, Sasha Hinkley, Tad Komacek, Katherine Morris, Lorenzo Pino, Sarah Rugheimer, Colin Snodgrass, Stephen Todd, Vinooja Thurairethinam, Amaury Triaud

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