Presentation #415.06 in the session “Asteroids: NEO Individual Characterization”.
As one of the largest Aten asteroids known, near-Earth asteroid 2100 Ra-Shalom has been extensively studied at visible, near-infrared, thermal-infrared, and radar wavelengths, but its physical nature is still poorly understood. We have utilized our shape-based thermophysical model SHERMAN to investigate the thermal properties of Ra-Shalom’s surface. This model has proven successful in constraining surface roughness, thermal inertia, and albedo of near-Earth asteroids [1,2]. Our thermal models for Ra-Shalom are constrained using new spectra we obtained at multiple viewing geometries in the near-infrared and thermal region at NASA’s Infrared Telescope Facility (IRTF) over the course of five nights in August-September 2019. For this study, we utilized the shape model of , which has a retrograde spin pole and agrees with all the lightcurve observations. The previous prograde-rotation, radar-derived shape model of  also provided thermal parameters for Ra-Shalom. Our goals are to determine whether a single set of homogeneous thermal properties can fit the observed spectra of Ra-Shalom, whether the  thermal properties are consistent with the observations, and how the thermal properties may depend upon the rotation pole direction for this asteroid.
We will present our initial assessment of the  thermal parameters when applied to our datasets. Preliminary model results using the published values from  show these values do not fit our spectra for Ra-Shalom. Our current best models suggest that a rougher surface and lower thermal inertias provide better fits between the models and data. We have yet to find a single range of parameters that fits all our spectra simultaneously, but we continue to model Ra-Shalom over a wider range of thermal parameters.
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