High quality optical photometry of NEOs in support of a Warm Spitzer program

Near Earth Objects (NEOs) may act as dynamical and compositional tracers of the history of near-Earth space. However, despite their scientific importance, key characteristics of the NEO population - such as the size distribution, mix of albedos and mineralogies, and contributions from so-called dead or dormant comets - remain largely unexplored; some 99% of all presently known NEOs are essentially uncharacterized. We have been awarded 500 hours of Warm Spitzer time to study ~700 NEOs. The Spitzer data will allow us to measure thermal fluxes and, in combination with optical data, derive albedos and diameters for a large fraction of all known NEOs. The primary uncertainty in our Spitzer results will derive from a lack of good optical photometry for our targets. We propose here a tightly focused program to obtain optical photometry of ~100 NEOs with a range of telescopes. These observations have been carefully planned to maximize efficiency and minimize demand on the largest telescopes, and are complemented by observations obtained elsewhere. The resulting photometry will enable our Warm Spitzer NEO science.