Reconciling main belt asteroid spectral flux density measurements with a self-consistent thermophysical model

Results of the infrared-to-centimeter comparisons confirm that low thermal inertia (I ∼ 5-80 J/(K m2 s0.5)) material constitutes the upper ∼1 cm of the four large asteroids studied. For the non-isothermal models considered, spectral emissivities near 1.0 fit the data of all four asteroids with no significant variations indicated throughout the infrared to microwave spectrum. Enhanced measured infrared flux levels (relative to a smooth surface model) of the four asteroids are constrained by a surface model with up to 50% fractional coverage of hemispherical craters, consistent with both the recent Lutetia result and historical measurements of the Moon's thermal flux characteristics.