Evaluation of CaSO4micrograins in the context of organic matter delivery: thermochemistry and atmospheric entry
| Autor: | Savino Longo, V. Piccinni, G. Micca Longo |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
chemistry.chemical_classification
Gypsum Materials science Anhydrite 010504 meteorology & atmospheric sciences Physics and Astronomy (miscellaneous) Evaporation Context (language use) engineering.material 01 natural sciences chemistry.chemical_compound Bassanite chemistry Chemical engineering Space and Planetary Science 0103 physical sciences Earth and Planetary Sciences (miscellaneous) engineering Thermochemistry Organic matter 010303 astronomy & astrophysics Ecology Evolution Behavior and Systematics Chemical decomposition 0105 earth and related environmental sciences |
| Zdroj: | International Journal of Astrobiology. 18:345-352 |
| ISSN: | 1475-3006 1473-5504 |
| DOI: | 10.1017/s1473550418000204 |
| Popis: | In this paper, anhydrous calcium sulphate CaSO4(anhydrite) is considered as a carrier material for organic matter delivery from Space to Earth. Its capability of incorporating important fractions of water, leading to different species like bassanite and gypsum, as well as organic molecules; its discovery on Mars surface and in meteorites; the capability to dissipate much energy by its chemical decomposition into solid (CaO) and gaseous (SO3) oxide, make anhydrite a very promising material in an astrobiological perspective. Since chemical cooling has been recently considered by some of the present authors for the case of Ca/Mg carbonates, CaSO4can be placed into a class of ‘white soft minerals’ (WSM) of astrobiological interest. In this context, CaSO4is evaluated here by using the atmospheric entry model previously developed for carbonates. The model includes grain dynamics, thermochemistry, stoichiometry, radiation and evaporation heat losses. Results are discussed in comparison with MgCO3and CaCO3and show that sub-mm anhydrite grains are potentially effective organic matter carriers. A Monte Carlo simulation is used to provide distributions of the sulphate fraction as a function of altitude. Two-zone model results are presented to support the isothermal grain hypothesis. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|