Radiative transfer models are some of the most widely used tools for compositional analyses of planetary bodies and have the opportunity to provide a comprehensive understanding of asteroid surface properties when used in conjunction with thermal modeling. We present the limitations and sensitivities of a new implementation of Hapke radiative transfer modeling using visible to near-infrared spectroscopy as a means for characterizing and constraining the surface properties of unresolved asteroids. These spectroscopically derived properties are complimentary to constraints from thermophysical models of data at longer wavelengths. This visible and near-infrared spectroscopic approach benefits from observational requirements that are less time intensive and less reliant on specialized instrumentation, and thus has the potential to characterize a large number of near-Earth and Main Belt asteroids.
Currently, our model is optimized for investigating S/Q-type asteroids whose spectra are dominated by 1 and 2 micron olivine and pyroxene absorption bands. We generate visible to near-infrared spectra using a simple three mineral model which encompasses the mineralogy range seen in ordinary chondrite meteorites for olivine, pyroxene, and iron metal, and adopts the scattering properties of well-studied S-type asteroids like Eros and Itokawa.
We will discuss our findings on the sensitivities and limitations of our technique and its ability to constrain grain size properties for select ordinary chondrite meteorite samples. We will also present the spectroscopic application of our technique with comparisons to ground truth and thermal regolith constraints for Eros and Itokawa.
This work is supported by the NASA NEOO program, grant number NNX17AH06G.