Bolometric albedo (A), color temperature (B), superheating factor (C), and dust color (D) as a function of time with respect to perihelion. The color of the symbols is according to elevation (as indicated in the color bar). The phase angle is plotted as a dashed line in plots A, C, and D. The dashed line in plot B is the color temperature obtained for a value of the superheating factor of 1.19 and a heliocentric variation following (Eq. (1)). The fitted spectra fulfill the condition TEST_3.0 < 1.35.