IRTF Data Archive Program Information

# # Program information file # PROGRAM_ID 2022A069 PROGRAM_TITLE Investigating the regolith properties of NEAs: Thermophysical modeling constrained by IRTF/SpeX observations and shape information PROGRAM_INV1 Ellen Howell PROGRAM_INV2 Ronald Vervack PROGRAM_INV3 Yanga Fernandez PROGRAM_INV4 Mary Hinkle PROGRAM_INV5 Kiana McFadden PROGRAM_SCICAT near-Earth objects PROGRAM_ABSTRACT_BEG We propose to measure both reflected and thermal spectra of near-Earth asteroids [NEAs] between 0.7-5.1 microns with SpeX. Our ongoing goal is to investigate the regolith properties of small NEAs by using detailed thermophysical models incorporating the shape and spin state. We explore 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 other 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. By comparing the thermal model results using detailed shape models versus lightcurve shape models we will examine the importance of concavities and surface features to the derived thermal parameters. We propose to observe five NEAs this semester. All of these objects are scheduled for radar observations at Goldstone, and all but 2001 SN26 are potentially hazardous [PHAs]. Asteroids 2001 SN263 [triple system], 1996 FG3 [binary system] and 7335 [1989 JA] have existing radar data and well-constrained shape models. Previous SpeX LXD observations exist for 2001 SN263 and 1996 FG3, which will allow us to validate our thermal models across apparitions. For each NEA we will use prism mode [0.7-2.5 microns] for mineralogy and to measure the reflected component of the spectrum, and we will use LXD-long 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. The total time request of 44 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