Narrow- and broad-band photometry of the peculiar comet 21P/Giacobini-Zinner during its 2018 apparition

We report on narrow- and broad-band photometry of the Jupiter Family Comet (JFC) 21P/Giacobini-Zinner observed, over than 8 months continuously, with both TRAPPIST telescopes (TN and TS). We monitored the evolution of the gaseous species production rates OH, NH, CN, C3 and C2 as well as the evolution of the Afhro parameter, a dust proxy. Measurements on the production rates and their ratios with respect to CN and to OH will be discussed. The peak of the water production was on August 17, 2018 (rh=1.07 au), 24 days before the perihelion, and it reached (3.72±0.05).10^28 molecules/s, while the peak value of Afrho was (575±12) cm. Comparison of the coma morphology features and the coma colors will be discussed.