Abstracts Astronomy & Space Science

Characterizing the Effects of Porosity and Particle Size on TIR Emissivity Spectral Features of Olivine

by Ryan Galinkin

We generated a series of 15 particulate San Carlos olivine samples with varying porosity and particle size. We created five different particle size distributions and each particle size distribution was prepared with three different packing techniques. These samples were then imaged under a microscope and a binarization thresholding technique was used to determine each sample's surface porosity by the ratio of dark, void pixels to the total number of pixels in each image. Our results show that we could estimate surface porosity from the analysis of a microscopic image, a non-destructive technique. These samples were then placed in the Planetary Analogue Surface Chamber for Asteroid and Lunar Environments (PASCALE) and their thermal infrared (TIR) emissivity spectra were measured under ambient or Earth-like conditions. We selected key diagnostic spectral features and compared how these features changed with increased porosity and reduced particle size. From this investigation, we concluded that the spectral effects due to surface porosity and particle size could only be uniquely distinguished from one another when we observed shifts in the transparency feature due solely to changes in porosity.