TY  - JOUR
A1  - Pittarello, Lidia
A1  - Goderis, Steven
A1  - Soens, Bastien
A1  - McKibbin, Seann J.
A1  - Giuli, Gabriele
A1  - Bariselli, Federico
A1  - Dias, Bruno
A1  - Helber, Bernd
A1  - Lepore, Giovanni Orazio
A1  - Vanhaecke, Frank
A1  - Köberl, Christian
A1  - Magin, Thierry E.
A1  - Claeys, Philippe
T1  - Meteoroid atmospheric entry investigated with plasma flow experiments: Petrography and geochemistry of the recovered material
JF  - Icarus : international journal of solar system studies
N2  - Melting experiments attempting to reproduce some of the processes affecting asteroidal and cometary material during atmospheric entry have been performed in a high enthalpy facility. For the first time with the specific experimental setup, the resulting material has been recovered, studied, and compared with natural analogues, focusing on the thermal and redox reactions triggered by interaction between the melt and the atmospheric gases under high temperature and low pressure conditions. Experimental conditions were tested across a range of parameters, such as heat flux, experiment duration, and pressure, using two types of sample holders materials, namely cork and graphite. A basalt served as asteroidal analog and to calibrate the experiments, before melting a H5 ordinary chondrite meteorite. The quenched melt recovered after the experiments has been analyzed by mu-XRF, EDS-SEM, EMPA, LA-ICP-MS, and XANES spectroscopy. The glass formed from the basalt is fairly homogeneous, depleted in highly volatile elements (e.g., Na, K), relatively enriched in moderately siderophile elements (e.g., Co, Ni), and has reached an equilibrium redox state with a lower Fe3+/Fe-tot ratio than that in the starting material. Spherical objects, enriched in SiO2, Na2O and K2O, were observed, inferring condensation from the vaporized material. Despite instantaneous quenching, the melt formed from the ordinary chondrite shows extensive crystallization of mostly olivine and magnetite, the latter indicative of oxygen fugacity compatible with presence of both Fe2+ and Fe3+. Similar features have been observed in natural meteorite fusion crusts and in micrometeorites, implying that, at least in terms of maximum temperature reached and chemical reactions, the experiments have successfully reproduced the conditions likely encountered by extraterrestrial material following atmospheric entry.
KW  - Melting experiments
KW  - Atmospheric entry
KW  - Meteorites
KW  - Fusion crust
KW  - Redox
Y1  - 2019
U6  - https://doi.org/10.1016/j.icarus.2019.04.033
SN  - 0019-1035
SN  - 1090-2643
VL  - 331
SP  - 170
EP  - 178
PB  - Elsevier
CY  - San Diego
ER  -