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Astrochemistry: May 2019


At the low temperatures (∼10 K) and high densities (∼100,000 H2 molecules per cc) of molecular cloud cores and protostellar envelopes, a large amount of molecular species (in particular those containing C and O) freeze-out onto dust grain surfaces.

We study the chemical evolution of H2O:CO:NH3 ice mixtures irradiated with soft X-rays, in the range 250-1250 eV. We identify many nitrogen-bearing molecules such as e.g., OCN-, NH4+ , HNCO, CH3CN, HCONH2, and NH2COCONH2.

Non-thermal desorption from icy grains containing H2CO has been invoked to explain the observed H2CO gas phase abundances in ProtoPlanetary Disks (PPDs) and Photon Dominated Regions (PDRs).

Formic acid (HCOOH) and carbon dioxide (CO2) are simple species that have been detected in the interstellar medium.

A number of recent experimental studies have shown that solid-state complex organic molecules (COMs) can form under conditions that are relevant to the CO freeze-out stage in dense clouds.

Two cosmochemists at Arizona State University have made the first-ever measurements of water contained in samples from the surface of an asteroid. The samples came from asteroid Itokawa and were collected by the Japanese space probe Hayabusa.