Astrochemistry

Introduction

Astrochemistry is the study of the abundance and reactions of molecules in the Universe, and their interaction with radiation. The discipline is an overlap of astronomy and chemistry. The word "astrochemistry" may be applied to both the Solar System and the interstellar medium. The study of the abundance of elements and isotope ratios in Solar System objects, such as meteorites, is also called cosmochemistry, while the study of interstellar atoms and molecules and their interaction with radiation is sometimes called molecular astrophysics. The formation, atomic and chemical composition, evolution and fate of molecular gas clouds is of special interest, because it is from these clouds that solar systems form.

History

One particularly important experimental result is the identification of molecular ions. These ions, identified via radio telescope, represent important intermediate steps in molecular formation and destruction. The ions help give clouds their shape and help them to maintain their density.

Observational Astrochemistry

Observational astrochemistry is the detection and study of interstellar molecules. The list of interstellar molecules contains molecular species that have been detected in the interstellar medium and circumstellar shells, grouped by the number of component atoms. The molecules may range from simple diatomic species to polyatomic molecules. The discovery of interstellar molecules begins with the detection of atomic hydrogen and then molecular hydrogen.

Astronomical observatory under a starry night sky.

Theoretical Astrochemistry

Theoretical astrochemists use the tools of quantum mechanics to model the behavior of molecules and atoms in the interstellar medium. These models can then be used to interpret observational data, and to predict new molecules that might be observed in the future. Theoretical astrochemistry may also use the results of laboratory experiments to refine and expand their models.

Laboratory Astrochemistry

Laboratory astrochemistry studies involve the simulation of conditions in outer space in order to form molecules that might be present in outer space. These molecules are then studied using spectroscopy in order to determine their composition and structure. The results of these experiments can be used to refine theoretical models, and to guide astronomers in their search for new interstellar molecules.

Astrochemical Processes

Astrochemical processes are those chemical reactions that occur in outer space. These processes can occur in a variety of locations, including interstellar clouds, circumstellar disks, and planetary atmospheres. The types of reactions and the species involved can vary widely, depending on the environment. Some of the most common processes include ionization, dissociation, and recombination reactions.

Astrobiology and Astrochemistry

Astrobiology is a related field that explores the possibility of life beyond Earth, and how life forms in the universe. Astrochemistry contributes to astrobiology by providing the chemical building blocks needed for life. The study of the formation of complex organic molecules in the interstellar medium and their incorporation into planetary systems is a major focus of astrochemistry.