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On the origins of backscattered solar wind energetic neutral hydrogen from the Moon and Mercury
Verkercke, S.; Leblanc, F.; Tramontina, D. +8 more
The surfaces of planetary airless bodies are directly bombarded by solar particles. The most abundant of those particles are solar wind protons. In the case of the Moon, many in situ observations have shown that a significant portion of these incident solar-wind protons are backscattered as energetic neutral hydrogen atoms (ENA). Measurements of t…
Insights into the interaction between defrosting seasonal ices and gully activity from CaSSIS and HiRISE observations in Sisyphi Cavi, Mars
Pajola, M.; Munaretto, G.; Vincendon, M. +10 more
Martian gullies are surface features, typically composed of an alcove, a channel and a depositional apron. They have been extensively studied since their first observations in the 2000s and were initially attributed to the action of liquid water. Later studies highlighted that their activity is spatially and temporally correlated with the seasonal…
A novel methodology to estimate pre-atmospheric dynamical conditions of small meteoroids
Weryk, Robert; Janches, Diego; Stober, Gunter +5 more
Recent observations using the Wind and Ulysses spacecrafts and the Solar Occultation For Ice Experiment (SOFIE) during the period between 2007 and 2020 indicate a total cosmic dust influx at Earth ranging from 22 to 32 tonnes per day. Much is still unclear about the formation, evolution, and propagation of this cosmic dust throughout our Solar Sys…
On structural properties of Comet 67/P dust particles collected in situ by ROSETTA/COSIMA from observations of electrical fragmentation
Klaus, Hornung; Eva, Maria Mellado; Oliver, J. Stenzel +20 more
After landing on the target, the kinetic energy can be dissipated within the fragment if it consists of many elements (as in the example of the Kerttu-Ender fragment, Fig. 2). If it consists of only a few elements, as is the case for most fragments traveling longer distances, the kinetic energy is dissipated by rolling. In the case of impact fragm…
Targeting and image acquisition of Martian surface features with TGO/CaSSIS
Cremonese, G.; Thomas, N.; Pommerol, A. +12 more
CaSSIS is a high-resolution visual telescope onboard the ExoMars Trace Gas Orbiter. The mission started the primary science phase in April 2018. The relatively small single image footprint (typically 40 km × 9.5 km) when compared to the total surface area of Mars demands that images should be targeted and target selection is key for the science re…
Comparative analysis of photometric parameters over Apollo landing sites from Terrain Mapping Camera (Chandrayaan-1/2) and lab measured data
Arya, A. S.; Nagori, Rohit; Dagar, Aditya K.
Terrain Mapping Camera (TMC) onboard Chandrayaan-1/2 have provided high spatial resolution (∼5m) panchromatic images in three stereo-views of fore, nadir and aft, (-25⁰, 0⁰, 25⁰), respectively. This study presents the comparative analysis of photometric properties in visible domain from TMC and lab measured data over Apollo 11, 12, 16 and 17 landi…
Astrometry with PRAIA
Assafin, M.
PRAIA - Package for the Reduction of Astronomical Images Automatically - is a suite of astrometric and photometric tasks designed to cope with huge amounts of heterogeneous observations with fast processing, no human intervention, minimum parameterization and yet maximum possible accuracy and precision. It is the main tool used to analyse astronom…
Cloud chemistry on Venus: Sulfuric acid reactions and supercooling in Venus liquid cloud droplets
Baines, K. H.; Delitsky, M. L.
Cloud particles on Venus consist of liquid droplets of aqueous sulfuric acid solutions (H2SO4/H2O) that are the site of chemical reactions arising from uptake (absorption) of surrounding gas molecules into the droplets and subsequent solution chemistry. The Henry's Law constant, H*, for HCl in sulfuric acid in wate…
Effects of stealth CME to ion energisation at ionospheric altitudes of Mars
Thampi, Smitha V.; Venkataraman, V.
The declining phase of Solar cycle 24 produced a slow coronal mass ejection (CME), which was categorized as stealth CME based on the absence of associated low coronal signatures. This CME impacted Mars and caused a major space weather event during 27-28 August 2018 (max vsw = 580 km s-1 near 1.5 AU). The impact of the stealth…
Preface for special issue on the Colour and Stereo Surface Imaging System (CaSSIS) at Mars
Sefton-Nash, Elliot; Wilson, Colin; Hauber, Ernst +2 more
The Colour and Stereo Surface Imaging System (CaSSIS) is the main camera on board the ExoMars Trace Gas Orbiter (TGO). Following launch of TGO on 14 March 2016, CaSSIS began nominal science operations in April 2018. At the time of writing CaSSIS has acquired an average of 21 observations per day, totaling 20.5 Tbits of downlinked telemetry, and ha…