Organic Material on Ceres: Insights from Visible and Infrared Space Observations.

The NASA/Dawn mission has acquired unprecedented measurements of the surface of the dwarf planet Ceres, the composition of which is a mixture of ultra-carbonaceous material, phyllosilicates, carbonates, organics, Fe-oxides, and volatiles as determined by remote sensing instruments including the VIR imaging spectrometer. We performed a refined analysis merging visible and infrared observations of Ceres' surface for the first time. The overall shape of the combined spectrum suggests another type of silicate not previously considered, and we confirmed a large abundance of carbon material.

Ammonium salts are a reservoir of nitrogen on a cometary nucleus and possibly on some asteroids.

The measured nitrogen-to-carbon ratio in comets is lower than for the Sun, a discrepancy which could be alleviated if there is an unknown reservoir of nitrogen in comets. The nucleus of comet 67P/Churyumov-Gerasimenko exhibits an unidentified broad spectral reflectance feature around 3.2 micrometers, which is ubiquitous across its surface.

The mechanism of hexamethylenetetramine (HMT) formation in the solid state at low temperature.

There is convincing evidence that the formation of complex organic molecules occurred in a variety of environments. One possible scenario highlights the universe as a giant reactor for the synthesis of organic complex molecules, which is confirmed by numerous identifications of interstellar molecules. Among them, precursors of biomolecules are of particular significance due to their exobiological implications, and some current targets concern their search in the interstellar medium as well as understanding the mechanisms of their formation.