  Near Earth Objects (NEOs) are fragments of remnant primitive bodies that date
from the era of Solar System formation. At present, the physical properties and
origins of NEOs are poorly understood. We have measured thermal emission from
three NEOs -- (6037) 1988 EG, 1993 GD, and 2005 GL -- with Spitzer's IRAC
instrument at 3.6, 4.5, 5.8, and 8.0 microns (the last object was detected only
at 5.8 and 8.0 microns). The diameters of these three objects are 400 m, 180 m,
and 160 m, respectively, with uncertainties of around 20% (including both
observational and systematic errors). For all three the geometric albedos are
around 0.30, in agreement with previous results that most NEOs are S-class
asteroids. For the two objects detected at 3.6 and 4.5 microns, diameters and
albedos based only on those data agree with the values based on modeling the
data in all four bands. This agreement, and the high sensitivity of IRAC, show
the promise of the Spitzer Warm Mission for determining the physical parameters
for a large number of NEOs.
