Investigations of the evolution of complex organic biomolecules from the interstellar medium to the Solar System

Project Title: Investigations of the evolution of complex organic biomolecules from the interstellar medium to the Solar System

Principle Investigator: Christopher Bennett

Pictured is an example of an ultra-high vacuum (UHV) surface science set-up that is used to simulate the conditions of different space environments down to 10 K in temperature. It currently incorporates both UV photon and keV electron radiation sources, visible-NIR-MidIR spectroscopy and a high-sensitivity mass spectrometer.

Project Description:
Research conducted within the Bennett Lab centers on simulating the conditions of either the space environment or on the primordial Earth where we are interested in understanding how complex organic biomolecules can be formed. To simulate the conditions of space we rely on ultrahigh vacuum (UHV; 10-10 torr) chambers that are equipped with different radiation sources to mimic the different environments to which the surfaces of interstellar ices, comets, icy rings or moons, or asteroids are exposed. In the Solar System, space weathering is responsible for the modification of the outer layers of surfaces exposed to solar UV photons and charged particles. In the interstellar medium (ISM), small icy grains may be exposed to high energy galactic cosmic rays (GCRs; e.g., 300 MeV H+ ions), which we mimic using keV electrons. We have two separate chambers; one to study the effects on minerals, or meteorites and a second to study irradiation effects on condensed volatiles (or ices). Simple volatiles (such as water, H2O, but also species such as methane, CH4, carbon dioxide, CO2, methanol, CH3OH, etc.) are found within ISM ices as well as cometary ices, and when irradiated, these can produce complex organic biomolecules which may be important to life, such as amino acids. We utilize primarily visible, near-IR and mid-infrared spectroscopy and mass spectrometry techniques to analyze chemical changes that are induced during the radiation process. Additionally, we also perform ab initio and density functional theory calculations to simulate the spectral properties of novel molecules that can be produced during the unusual conditions encountered within our ices. Lastly, we perform experiments simulating the conditions on the primordial Earth to see if we can induce the polymerization of small units (such as amino acids) into larger oligomer chains (such as peptides) by heating simple solutions on mineral surfaces.

Successful applicants who are interested in performing summer projects in this group will aid in conducing either experimental or theoretical investigations under the supervision of Dr. Bennett and graduate students within his research group. Such projects may include: (I) the production of new chemical species within radiated ices representative of interstellar or Solar System bodies, (II) theoretical calculations simulating the optical properties of unstable chemical species, (III) helping to perform simulations of the primordial Earth environments, or (IV) helping to install and calibrate a Raman spectrometer. The student would be expected to participate in daily experiments or calculations within the laboratory, but the specifics will likely be determined at the time the program begins.