IR Techniques to Detect and Characterize NEOs
Mainzer, Amy¹; Wright, E.²; McMillan, R.³; Eisenhardt, P.¹; Trilling, D.⁴; Walker, R.^5
1Jet Propulsion Laboratory; ²UCLA; ³University of Arizona; ⁴Northern Arizona University; ⁵MIRA

An accurate knowledge of the size and composition of near-Earth objects (NEOs) is critical to understanding both their role in solar system science as well as hazard analysis. The visible light flux of most NEOs is strongly affected by their albedo, resulting in a degeneracy between optical fluxes of high albedo objects of small sizes and large objects with low albedos. Although recent work has provided constraints on the mean albedo of NEOs, uncertainties still remain in the NEO size frequency distribution. Observing NEOs in the infrared near the peak of their thermal flux can result in an intrinsically more accurate measurement of diameter, since their infrared flux is a weaker function of albedo than visible flux.
Additionally, infrared and visible fluxes can be combined to yield albedo, which serves as a proxy for composition. Infrared observatories can also be a powerful tool for detecting large numbers of NEOs, given their intrinsic sensitivity to low albedo objects. There are several upcoming projects which promise to confirm and extend our knowledge of the size frequency distribution, albedo distribution, and the effect of the Yarkovsky force on NEOs.