Seasonal southern circum-polar spots and araneiforms observed with the colour and stereo surface imaging system (CaSSIS)

Cesar, Camila; Pommerol, Antoine; Thomas, Nicolas; Portyankina, Ganna; Hansen, Candice J.; Tornabene, Livio L.; Munaretto, Giovanni; Cremonese, Gabriele (2022). Seasonal southern circum-polar spots and araneiforms observed with the colour and stereo surface imaging system (CaSSIS). Planetary and space science, 224, p. 105593. Elsevier 10.1016/j.pss.2022.105593

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The southern polar area of Mars is home to various seasonal activity commonly explained by the Kieffer model.
During southern spring, the ice covering the polar area sublimates and leaves distinct features (spiders, spots,
fans) observable from orbit. The Colour and Stereo Surface Imaging System (CaSSIS) onboard the ExoMars Trace
Gas Orbiter (TGO), provides high-resolution multi-filter images of the Martian surface offering high sensitivity to
colour contrasts. Its stereo capability is pivotal for momentary processes and offers a unique perspective for
studying surface sublimation processes and their relation to atmospheric features. For the first time, we identify
clouds well correlated with surface features (araneiforms and spots at southern circum-polar latitudes) hence
motivating a new campaign to refine these observations over time periods where CO2 sublimation processes
occur. We focus here on the structure of spot deposits and their evolution through time. We identify and describe
seven structures: dark spot, bright-haloed spot, ringed spot, inverted spot, dark-haloed spot, banded spot, and
bright spot. By morphological and spectral analyses, we hypothesize a new chronology of events that characterise
the origin, formation and evolution of these features.

Item Type:

Journal Article (Original Article)


08 Faculty of Science > Physics Institute > Space Research and Planetary Sciences
08 Faculty of Science > Physics Institute
08 Faculty of Science > Physics Institute > NCCR PlanetS

UniBE Contributor:

Cesar, Camila, Pommerol, Antoine, Thomas, Nicolas


500 Science > 530 Physics
500 Science > 520 Astronomy
600 Technology > 620 Engineering








Dora Ursula Zimmerer

Date Deposited:

16 Mar 2023 07:47

Last Modified:

16 Mar 2023 23:27

Publisher DOI:





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