Astrokemi

Astrokemi, or astrochemistry, is the scientific study of chemical processes in astronomical environments. It explores how atoms and molecules form, persist, and react in space, including the interstellar medium, circumstellar envelopes around evolved stars, protoplanetary disks, comets, and planetary atmospheres. The field integrates chemistry, physics, and astronomy to understand the chemical evolution of the universe.

The research topics encompass gas-phase reactions, chemical interactions between gas and dust grains, photochemistry driven by ultraviolet radiation, and processing by cosmic rays and shocks. In cold regions, much of the chemistry occurs on the surfaces of dust grains, where atoms and simple molecules assemble into more complex species and later return to the gas phase through desorption or energetic processing. Temperature, density, radiation fields, and grain properties strongly influence the chemistry observed in different environments.

Methodologically, astrochemists rely on observational spectroscopy across radio, millimeter, and infrared wavelengths to identify molecules and measure their abundances. Laboratory experiments reproduce interstellar ices and reaction conditions, while theoretical calculations and chemical networks predict reaction rates and the formation pathways of known and anticipated species. Isotopic ratios and molecular excitation conditions provide additional diagnostics of physical environments.

Astrochemistry examines environments such as cold dark clouds, warm hot cores around forming stars, and evolving protoplanetary disks, as well as the chemistry of comets and planetary atmospheres. It seeks to explain the origin of complex organic molecules and prebiotic precursors, informing theories of star and planet formation and the chemical basis of the emergence of life. Advances come from new observational facilities and improved models that broaden the inventory of detectable species.