Publication
Names
  • S. Philippe
Title
Microphysique des processus saisonniers des glaces de Mars et Pluton : suivi par télédétection hyperspectrale et étude expérimentale
Abstract
The condensation/sublimation cycle of $CO_2$ controls the martian climate and, in winter, forms frozen seasonal deposits, contaminated with water ice and dust. This thesis’ objective is to understand, characterize, and if possible, to quantify the different microphysical processes occuring in the seasonal deposits during this condensation/sublimation cycle, with the insight of experimental simulation of these processes inside the CarboN-IR experimental cell. The $CO_2$ ice condensation in a polycristalline form on a mineral regolith, the modification of the $CO_2$ ice condensation regime in the martian polar night due to the presence of non condensable gases, the stratification of water ice onto $CO_2$ ice during the sublimation of the seasonal deposits and the increase of the albedo of $CO_2$ slab ice during its springtime sublimation are all phenomena that have been reproduced successfully inside the experiemental cell. The $CO_2$ slab ice condensation on the Martian surface has been observed during its formation, in autumn, at lower latitudes than polar night limit with hyperspectral imaging from the OMEGA spectrometer onboard of the Mars Express probe. Yet the farthest object explored in the solar system, Pluto, shares many similarities with Mars, particularly a partial icy cover of its surface (of $CH_4$, $N_2$ and $CO$ ices for Pluto) in equilibrium with its atmosphere. The evolution of these ices can be considered similar in terms of the surface processes affecting them : stratification of ices in function of their volatility during their sublimation or condensation at the surface, formation of slab ice ... The hyperspectral imagery data (LEISA), provided by the New Horizons probe during its Pluto’s flyby in july 2015, allowed to determine the accurate cartography of chemical species at the surface, along with their physical state - the preliminary steps of any geological interpretation.
Keywords
spectroscopy, thermodynamics, sample cell, spectro-gonio radiometer, bidirectional reflection, radiative transfer simulation, bidirectional reflectance spectra, visible, near-IR, thermal process, fluid process, condensation, sublimation, kinetic, grain size, molecular solid, ice, snow, CO2, H2O, N2, CH4, CO, Mars, Pluton, surface
Content
instrument-technique, sample, material-matter, spectral data, thermodynamic data, planetary sciences
Document type
phd thesis
Year
2016
Pages
1 - 379
Pages number
379
Editor
IPAG
Publisher
Université Grenoble Alpes
Publisher city
Grenoble, France
Publication state
published
Comments
PhD defence: 5 December 2016