1. Mineralogical studies of Silicate stardust in the laboratory A. N
Mineralogical studies of Silicate stardust in the laboratory A. N. Nguyen1,2, L. P. Keller1, S. Messenger1, K. Nakamura-Messenger1, and Z. Rahman1,2 1Robert M. Walker Laboratory for Space Science, ARES, NASA JSC, 2Jacobs Technology, Houston TX, USA
Laboratory analyses of the mineral and chemical properties of silicate stardust grains mostly agree with astronomical observations
Majority of grains are Fe-bearing amorphous silicates with non-stoichiometric compositions
Crystalline silicates make up ~1/3 of analyzed grains. This abundance is much greater than the fraction observed in the ISM (< 1%)
Suggests recrystallization of amorphized grains or preferential destruction of amorphous silicates
Olivine grains have higher Fe-contents than pyroxene grains
Amorphization in space is rare
Two amorphized grains have been observed
Laboratory analyses of silicate stardust unveil details that cannot be observed remotely
Many grains (~20%) are aggregates of amorphous and crystalline silicate phases, or compound silicate and oxide grains
Some grains have FeNi metal inclusions
Mg Si Fe
Pyroxene
Olivine