Issue |
A&A
Volume 402, Number 1, April IV 2003
|
|
---|---|---|
Page(s) | 373 - 381 | |
Section | Planets and planetary systems | |
DOI | https://doi.org/10.1051/0004-6361:20030027 | |
Published online | 07 April 2003 |
Mars: Mapping surface units by means of statistical analysis of TES spectra
CNR, Istituto di Fisica dello Spazio Interplanetario 00133 Rome, Italy
Corresponding author: F. Altieri, francesca.altieri@isfi.rm.cnr.it
Received:
28
November
2001
Accepted:
3
December
2002
Thermal Emission Spectrometer (TES) data from the Mars
Global Surveyor (MGS) mapping phase have been processed to
identify regions with unique spectral features for new clues on
the Martian surface composition. For this purpose we have
developed a procedure to search and map band absorptions related
to presence of different surface minerals on a spatial scale of a
few kilometers. Data used in this study cover the March 1999–July 2000 period, corresponding to on Nili Fossae, Sinus Meridiani and
Valles Marineris regions, where outcrops of olivines and hematite have been
identified in previous studies. We have tested the validity of our
procedure on these areas and then extended our analysis to other
portions of the planet. The data have been assembled in
emissivity spectra cubes with
pixels per square degree. The Principal Components Analysis (PCA)
has been used to identify spectra with very low contamination by
atmospheric aerosols. It has been applied in two spectral ranges:
cm-1 (~18.2–33.3 μm) and 815–1143 cm-1 (~8.7–12.3 μm). By means of PCA we have
selected three principal spectral classes: spectra with a high
content of dust, spectra with a high content of water-ice and
spectra with a lower contamination by dust and water-ice. To
identify emission spectra with interesting features likely related
to surface minerals we have selected, in the last class, data with
high spectral variance between 300–550 cm-1, the range
where the hematite and olivine bands have been found.
Key words: planets and satellites: individual: Mars / techniques: spectrometric / methods: data analysis
© ESO, 2003
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