Report from ISSI Team #397 Comet 67P/Churyumov-Gerasimenko Surface Composition as a Playground for Radiative Transfer Modeling and Laboratory Measurements” led by M. Ciarniello
Recent investigations of the surface composition of comet 67P/Churyumov-Gerasimenko, by means of observations provided by the VIRTIS imaging spectrometer onboard the Rosetta mission, revealed the presence of aliphatic organics and ammonium salts, which characterize the ubiquitous 3.2 µm absorption band in the comet’s infrared spectrum. (See ISSI Team Report from April 9, 2020)
Here we report of a further laboratory investigation, which indicates that hydroxylated magnesium-rich amorphous silicates have spectral properties compatible with the infrared absorption observed on the comet 67P/Churumov-Gerasimenko. They can be an additional constituent of the comet’s surface. Hydroxylated amorphous silicates are formed upon interaction of hydrogen atoms with amorphous silicates. Such process can take place in the interstellar medium (ISM), and the presence of hydroxylated silicates on a cometary nucleus would represent an evolutionary linkbetween the ISM and the primitive objects in the Solar System. The link is consistent with the evolution of aliphatic organics, which also originate in the ISM.
The investigation took advantage, among other authors, of the collaboration of the ISSI Team “Comet 67P/Churyumov-Gerasimenko Surface Composition as a Playground for Radiative Transfer Modeling and Laboratory Measurements” led by M. Ciarniello and has been published in the paper
Hydroxylated Mg-rich Amorphous Silicates: A New Component of the 3.2 μm Absorption Band of Comet 67P/Churyumov–Gerasimenko by V. Mennella et al., 2020, The Astrophysical Journal Letters, Volume 897, Number 2, DOI: https://doi.org/10.3847/2041-8213/ab919e