Yu-Chi Cheng (NTNU-PHYS, OBSPM), Dominique Bockelée-Morvan (OBSPM), Stéphane Earad (OBSPM), Fabrizio Capaccioni (INAF-IAPS), Cédric Leyrat (OBSPM), Gianrico Filacchione (INAF-IAPS), and the VIRTIS team
Comet is the most ancient object in our solar system. Ice-rich cometary nuclei are believed as remnants of planetesimals forming billion years ago. The great success of the European Space Agency Rosetta rendezvous mission opened a new vision on the nature of comet 67P/Churyumov-Gerasimenko. In-situ observations from multiple instruments onboard the Rosetta spacecraft revealing unprecedented high-resolution images of the cometary surface, distribution of several chemical species in the coma environment, and other incredible scientific results we had never seen before. In this presentation, I will briefly introduce what we had learned from the Visible and InfraRed Thermal Imaging Spectrometer (VIRTIS) instrument, such as the H2O column density measurement, constraint the physical properties of the coma environment, and estimate the Ortho-to-Para ratio (OPR) of water.