No signature of clear CO2 ice from the 'cryptic' regions in Mars' south seasonal polar cap - INSU - Institut national des sciences de l'Univers Access content directly
Journal Articles Nature Year : 2006

No signature of clear CO2 ice from the 'cryptic' regions in Mars' south seasonal polar cap

Abstract

The seasonal polar ice caps of Mars are composed mainly of CO2 ice(1,2). A region of low (< 30%) albedo has been observed within the south seasonal cap during early to mid-spring(3,4). The low temperature of this 'cryptic region' has been attributed to a clear slab of nearly pure CO2 ice, with the low albedo resulting from absorption by the underlying surface(4). Here we report near-infrared imaging spectroscopy of the south seasonal cap. The deep and broad CO2 absorption bands that are expected in the near-infrared with a thick transparent slab of CO2 ice are not observed. Models of the observed spectra indicate that the low albedo results from extensive dust contamination close to the surface of a CO2 ice layer, which could be linked to atmospheric circulation patterns(5,6). The strength of the CO2 absorption increases after mid-spring, so part of the dust is either carried away or buried more deeply in the ice layer during the CO2 ice sublimation process.

Dates and versions

insu-00357235 , version 1 (29-01-2009)

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Y. Langevin, Sylvain Douté, M. Vincendon, F. Poulet, J.-P. Bibring, et al.. No signature of clear CO2 ice from the 'cryptic' regions in Mars' south seasonal polar cap. Nature, 2006, 442 (7104), pp.790-792. ⟨10.1038/nature05012⟩. ⟨insu-00357235⟩
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