Space weathering simulations through controlled growth of iron nanoparticles on olivine
| Autor: | Roman Skála, Radek Zbořil, Tomas Kohout, J. Čuda, Daniel T. Britt, Jiří Tuček, Todd Bradley, Jan Filip, Gunther Kletetschka, Ondřej Malina, Josef Kašlík, Karolina Siskova |
|---|---|
| Přispěvatelé: | Department of Physics, Planetary-system research |
| Jazyk: | angličtina |
| Rok vydání: | 2014 |
| Předmět: |
Thermal Emission Spectrometer
Materials science Population Analytical chemistry FOS: Physical sciences engineering.material Space weathering Astrobiology chemistry.chemical_compound Spectral slope Moon education Spectroscopy Earth and Planetary Astrophysics (astro-ph.EP) education.field_of_study Olivine Asteroids Surfaces Astronomy and Astrophysics 115 Astronomy Space science Silicate chemistry 13. Climate action Space and Planetary Science Absorption band engineering Regoliths Astrophysics - Earth and Planetary Astrophysics |
| Popis: | Airless planetary bodies are directly exposed to space weathering. The main spectral effects of space weathering are darkening, reduction in intensity of silicate mineral absorption bands, and an increase in the spectral slope towards longer wavelengths (reddening). Production of nanophase metallic iron (npFe$^{0}$) during space weathering plays major role in these spectral changes. A laboratory procedure for the controlled production of npFe$^{0}$ in silicate mineral powders has been developed. The method is based on a two-step thermal treatment of low-iron olivine, first in ambient air and then in hydrogen atmosphere. Through this process, a series of olivine powder samples was prepared with varying amounts of npFe$^{0}$ in the 7-20 nm size range. A logarithmic trend is observed between amount of npFe$^{0}$ and darkening, reduction of 1 {\mu}m olivine absorption band, reddening, and 1 {\mu}m band width. Olivine with a population of physically larger npFe$^{0}$ particles follows spectral trends similar to other samples, except for the reddening trend. This is interpreted as the larger, ~40-50 nm sized, npFe$^{0}$ particles do not contribute to the spectral slope change as efficiently as the smaller npFe$^{0}$ fraction. A linear trend is observed between the amount of npFe$^{0}$ and 1 {\mu}m band center position, most likely caused by Fe$^{2+}$ disassociation from olivine structure into npFe$^{0}$ particles. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|