12P/Pons-Brooks magnitude and activity

The spectra were used to analyse the emissions from the different molecular bands. We detect nine strong outbursts, with an approximate two-week periodicity; OH production rate reaching values above 10^29^ molecules/s and A(0)f{rho} dust activity proxy above 10^5^cm. Dust images show the formation of a double-horned-shaped coma and the expansion of a dust shell in the days following the strongest outbursts.

The gas-to-dust ratio behaviour during these events differs from other observations of outbursting comets closer to the Sun, while outbursts rather share similarities with the centaur comet 29P/Schwassmann-Wachmann's. The analysis of CN jets between 1.02 and 2.13au suggests a nucleus rotation period of either 29.45h or 58.90h and a gas ejection velocity of 1.03+/-0.09km/s. From the MISTRAL spectra, emission bands from C_2_, NH_2_, and CN were observed, as well as H_2_ O+ in the anti-sunward direction.