Mid-Infrared Observations of Near-Earth Objects from the newly refurbished mid-infrared instrument at the NASA-IRTF

We have carried out simultaneous thermal observations of ~14 near-Earth objects (NEOs) to measure their diameter and albedo. We have used the newly refurbished Mid-Infrared Spectrometer and Imager (MIRSI) at the NASA Infrared Telescope Facility (IRTF) to obtain the thermal observation with the N-band filter (10.5 μm). A unique capability of MIRSI is its optical camera (MOC; a clone of MORIS: the optical camera of Spex) which allows for simultaneous visible [r, i, z] photometry of NEOs for accurate albedo measurements. We will present diameters and albedos for these targets and our prospects for continued future NEO observations with MIRSI. Our targets have been selected upon semestral availability (Vmag<18) and thermal fluxes detectable by MIRSI within 30-45 minutes of observation. NEOWISE and Spitzer have already observed some objects so that we can cross-correlate our ground-based measurements with those obtained by space missions.

MIRSI's first light happened in September 2021, and science commissioning after January 2022. For more information about MIRSI (i.e., sensitivity and observing tips) and its status, please visit the IRTF web page (http://irtfweb.ifa.hawaii.edu/~mirsi/). Future NEOs observations with MIRSI+MOC will include characterization for mission support (i.e., DART mission) and multiwavelength characterization of selected targets. Given the current low number of available ground-based telescopes with mid-infrared cameras, MIRSI could serve as an essential instrument for thermal characterization for the planetary community.