χ² curves from fitting TPM predictions to the WISE and Spitzer-IRAC data for asteroid (17246) Christophedumas (left) and (22899) Alconrad (left). For Christophedumas, three different TPM solutions are shown: assuming a low, (dotted line), intermediate (default value; see Müller & Lagerros (1998)), and high level (dashed line) of surface roughness. The red parts show acceptable TPM settings with possible thermal inertias in the range between 4 and 50 J m⁻² s^−0.5 K⁻¹. For Alconrad, three different TPM solutions are shown for a prograde rotation of the primary (top 3 thin lines), and another three lines (thick dashed and solid lines) for the retrograde rotation case. Based on our radiometric study, the retrograde rotation is strongly favored, possibly with a thermal inertia in the 30-100 J m⁻² s^−0.5 K⁻¹ range. The retrograde rotation is in agreement with the retrograde orbit of the satellite.