Named in honor of Michel C. Festou of the Observatoire Midi-Pyrénées, Toulouse, for his extensive and wide-ranging studies of comets, both theoretical and observational. Festou was the first to calculate a vectorial model for the dissociation of water in cometary comae, and he has made major contributions to the theoretical understanding of emission by various species, including, for example, [O I] and CN. He has been a preeminent practitioner of ultraviolet spectroscopy of comets, identifying features due to OH+, CO2+ and [O I], and he has also contributed numerous ground-based observations of comets. (M 18462) _ _.