  The field of asteroid thermophysical modeling has experienced an
extraordinary growth in the last ten years, as new thermal infrared data became
available for hundreds of thousands of asteroids. The infrared emission of
asteroids depends on the body's size, shape, albedo, thermal inertia, roughness
and rotational properties. These parameters can therefore be derived by
thermophysical modeling of infrared data. Thermophysical modeling led to
asteroid size estimates that were confirmed at the few-percent level by later
spacecraft visits. We discuss how instrumentation advances now allow
mid-infrared interferometric observations as well as high-accuracy
spectro-photometry, posing their own set of thermal-modeling challenges.We
present major breakthroughs achieved in studies of the thermal inertia, a
sensitive indicator for the nature of asteroids soils, allowing us, for
instance, to determine the grain size of asteroidal regoliths. Thermal inertia
also governs non-gravitational effects on asteroid orbits, requiring
thermophysical modeling for precise asteroid dynamical studies. The radiative
heating of asteroids, meteoroids, and comets from the Sun also governs the
thermal stress in surface material; only recently has it been recognized as a
significant weathering process. Asteroid space missions with thermal infrared
instruments are currently undergoing study at all major space agencies. This
will require a high level of sophistication of thermophysical models in order
to analyze high-quality spacecraft data.
