Colors and morphology of sources of activity on 67P/Churyumov-Gerasimenko nucleus from OSIRIS/ROSETTA observations

International audienceThis work focuses on the identification of the regions sources of faint jets and outbursts on the 67P/CG nucleus, and on the study of their spectrophotometric properties, from observations acquired with the OSIRIS camera onboard ROSETTA during the July-October 2015 period, i.e. close to perihelion. More than 200 jets of different intensities were identified directly on the nucleus. Some spectacular outbursts appear spectrally blue, due to the presence of grains having very small size and possibly water ice enriched. Some jets have an extremely short lifetime, appearing on the cometary surface during the color sequence observations, reaching their peak in flux and then vanishing in less than a couple of minutes. These short lived events were observable thanks to the unprecedented spatial and temporal resolution of the ROSETTA/OSIRIS observations. We observed the sources of activity at higher resolution during the last months of operation of Rosetta, and we study the link between morphology, composition and activity on cometary nuclei