IRTF Data Archive Program Information

# # Program information file # PROGRAM_ID 2021A056 PROGRAM_TITLE Combining thermal observations and radar-derived shapes of near-Earth asteroids PROGRAM_INV1 Ellen Howell PROGRAM_INV2 Ron Vervack PROGRAM_INV3 Yanga Fernandez PROGRAM_INV4 Mary Hinkle PROGRAM_INV5 Kiana McFadden PROGRAM_SCICAT solar system PROGRAM_ABSTRACT_BEG We propose to measure both reflected and thermal spectra of near-Earth asteroids [NEAs] at 0.7-5.1 microns with SpeX. The objects are radar targets, for which detailed shape models and spin states have been or will be derived. Our ongoing goal is to investigate regolith properties of small NEAs by using detailed thermophysical models incorporating the radar shape and spin state. We are investigating how the complex shapes, spin states, and regolith properties of NEAs affect the thermal flux and their derived sizes and albedos by comparing our results to the more commonly used simple thermal models, such as NEATM. By observing these targets at multiple viewing geometries, we are also investigating the level of heterogeneity in the surface properties that is often required to explain the multiple thermal observations. We propose to observe five NEAs this semester. Targets 3103 Eger and 1990UQ already have existing radar data. We observed Eger previously, which will allow us to validate our thermal models across apparitions. For each NEA we will use the prism mode [0.7-2.5 microns] for mineralogy and to measure the reflected component of the spectrum, and we will use the LXD-long setting to measure the thermal flux between 2.0-5.1 microns. Observations of each object will be obtained at three different viewing geometries [i.e., on three different dates] at a minimum; overlap will lead to additional geometries for some targets. The total time request of 46 hours is based on previous experience with such observations, includes time for telescope slews, flats and arcs, and standard stars, and is optimized for the overlap between targets where possible for observing efficiency. PROGRAM_ABSTRACT_END