Proof of Concept for Spitzer Warm Mission Observations of Near Earth Objects

Near Earth Objects (NEOs) are fragments of remnant primitive bodies that date from the era of Solar System formation. NEO orbits bring these primordial samples close to the Earth, and studies of the composition of the material from which the planets formed may follow. However, at present, the physical properties and origins of NEOs are poorly understood. Characterizing NEOs is important because of the potential threat of an Earth impact and because they are the closest Solar System bodies to the Earth, and therefore the most easily explored. The Spitzer Warm Mission will have the unique capability of measuring the thermal emission and temperature for ~2000 NEOs in a pointed survey of ~1300 hours. The Spitzer data, when combined with ground-based optical data, will allow us to determine the sizes and albedos of individual NEOs and to obtain for the first time a size-frequency distribution for the NEO population down to sizes smaller than 1 kilometer. We propose here to observe three NEOs in a proof of concept experiment for potential observations in thee Spitzer Warm Mission. The NEOs proposed here are all smaller than one kilometer, more than an order of magnitude smaller than the smallest NEO that will be observed by WISE yet representative of an important subclass of objects. Pointing constraints make JWST much more inefficient at carrying out such a survey of NEO physical properties.