Hydroxylated Mg-rich Amorphous Silicates: A New Component of the 3.2 μ m Absorption Band of Comet 67P/Churyumov–Gerasimenko

Mennella, V.; Ciarniello, M.; Raponi, A.; Capaccioni, F.; Filacchione, G.; Suhasaria, T.; Popa, C.; Kappel, D.; Moroz, L.; Vinogradoff, V.; Pommerol, A.; Rousseau, B.; Istiqomah, I.; Bockelee-Morvan, D.; Carlson, R. W.; Pilorget, C. (2020). Hydroxylated Mg-rich Amorphous Silicates: A New Component of the 3.2 μ m Absorption Band of Comet 67P/Churyumov–Gerasimenko. Astrophysical Journal Letters, 897(2), L37. Institute of Physics Publishing IOP 10.3847/2041-8213/ab919e

Text Mennella_2020_ApJL_897_L37.pdf - Published Version Restricted to registered users only Available under License Publisher holds Copyright. Download (733kB) | Request a copy

The VIRTIS imaging spectrometer on board Rosetta has shown that the nucleus surface of comet 67P/Churyumov–Gerasimenko(67P/CG)is characterized by a broad absorption band at around 3.2μm. The feature isubiquitous across the surface and its attribution to(a)specific material(s)has been challenging. In the presentLetter, we report an experimental investigation showing that the interaction of hydrogen atoms with Mg-richamorphous silicates determines the formation of hydroxyl groups. The resulting IR spectrum exhibits a broadfeature around 3.2μm similar to that of comet 67P/CG. Hapke’s radiative transfer model was employed toestimate an upper limit contribution of 65% of hydroxylated silicates to the observed cometary band intensity. Thepresence of a hydroxylated fraction in silicates on the cometary surface would represent an evolutionary linkbetween primitive objects of the solar system and dust in the interstellar medium(ISM), where silicate grains canbe hydroxylated after having interacted with hydrogen atoms. This link is consistent with the detection of thealiphatic organics in 67P/CG that also originate in the ISM.

Interest & Impact

Downloads

1 since deposited on 10 Mar 2021
0 in the past 12 months

Citations

5 Citations in Web of Science ®
6 Citations in Scopus

Search

in Google Scholar™

Services

Actions (login required)

Edit item

Actions (login required)

Edit item