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The 17 April 2021 widespread solar energetic particle event
Holmström, M.; Grande, M.; Palmerio, E. +46 more
Context. A complex and long-lasting solar eruption on 17 April 2021 produced a widespread solar energetic particle (SEP) event that was observed by five longitudinally well-separated observers in the inner heliosphere that covered distances to the Sun from 0.42 to 1 au: BepiColombo, Parker Solar Probe, Solar Orbiter, STEREO A, and near-Earth space…
A Mars orbital catalog of aqueous alteration signatures (MOCAAS)
Bibring, Jean-Pierre; Langevin, Yves; Gondet, Brigitte +3 more
We describe the completion of the MOCAAS project providing a global repository of secondary minerals formed through interaction with water on Mars. This work is based on the analysis of orbital imaging spectroscopy data from the OMEGA/Mars Express and CRISM/MRO near-infrared instruments. A database and a set of high-resolution global maps (200 m/p…
Mineralogy, Morphology, and Emplacement History of the Maaz Formation on the Jezero Crater Floor From Orbital and Rover Observations
Liu, Yang; Horgan, Briony; Ravanis, Eleni +42 more
The first samples collected by the Perseverance rover on the Mars 2020 mission were from the Maaz formation, a lava plain that covers most of the floor of Jezero crater. Laboratory analysis of these samples back on Earth would provide important constraints on the petrologic history, aqueous processes, and timing of key events in Jezero crater. How…
Solar cycle variation of ion escape from Mars
Barabash, Stas; Nilsson, Hans; Zhang, Qi +6 more
Using Mars Express data from 2007 until 2020 we show how ion outflow from Mars varied over more than a solar cycle, from one solar minimum to another. The data was divided into intervals with a length of one Martian year, starting from 30 April 2007 and ending 13 July 2020. The net escape rate was about 5 × 1024s-1 in the fir…
High-resolution shape models of Phobos and Deimos from stereophotoclinometry
Barnouin, Olivier S.; Daly, R. Terik; Ernst, Carolyn M. +5 more
We created high-resolution shape models of Phobos and Deimos using stereophotoclinometry and united images from Viking Orbiter, Phobos 2, Mars Global Surveyor, Mars Express, and Mars Reconnaissance Orbiter into a single coregistered collection. The best-fit ellipsoid to the Phobos model has radii of (12.95 ± 0.04) km × (11.30 ± 0.04) km × (9.16 ± …
A Tectonic Origin for the Largest Marsquake Observed by InSight
Wilson, Colin; Lucas, Antoine; Tirsch, Daniela +23 more
The S1222a marsquake detected by InSight on 4 May 2022 was the largest of the mission, at MwMa 4.7. Given its resemblance to two other large seismic events (S1000a and S1094b), which were associated with the formation of fresh craters, we undertook a search for a fresh crater associated with S1222a. Such a crater would be exp…
The effects of atmospheric dust and solar radiation on the dayside ionosphere of Mars derived from 17 years of Mars Express radio science observations
Pätzold, M.; González-Galindo, F.; Witasse, O. +5 more
This work combines 17 years of Mars Express radio science (MaRS) observations with proxies for insolation and local/global atmospheric dust to investigate the combined and individual effects on the dayside ionosphere of Mars from the top down to the ionospheric base.
The increase in insolation from orbital apocenter to pericenter in combinati…Clay minerals on Mars: An up-to-date review with future perspectives
Ye, Binlong; Du, Peixin; Yuan, Peng +1 more
Clay minerals, or analogously phyllosilicates, are some of the most astonishing minerals ever discovered on Mars due to their roles as indicators of water-rock interaction. Their types, abundances, and locations provide hints to ancient environmental conditions of Mars and to the possible places where present-day mineral-bound water and/or biosign…
Morphology and paleohydrology of intracrater alluvial fans north of Hellas Basin, Mars
Williams, Rebecca M. E.; Anderson, Ryan B.; Gullikson, Amber L. +1 more
Alluvial fans and sinuous ridges are both important records of the history of fluvial activity on Mars, and they often occur together. We present observations of alluvial fans, many of which exhibit inverted relief, in five craters in the region north of Hellas basin. The observed fans ranged in size from ~10 to 820 km2. We identified t…
Radio Absorption in the Nightside Ionosphere of Mars During Solar Energetic Particle Events
Lester, M.; Leblanc, F.; Sánchez-Cano, B. +3 more
Characterization, understanding, and prediction of the Martian radio environment are of increasing importance to the forthcoming human exploration of Mars. Here we investigate 3-5 MHz radio absorption in the nightside ionosphere of Mars caused by enhanced ionization at <100 km altitudes during solar energetic particle (SEP) events. We conduct a…