Research in the Cooke Group focuses on laboratory surface and gas-phase experiments to unravel the formation of molecules in interstellar space. Our group aims to understand whether the chemical ingredients for life evolve in space and can be transferred to newly forming planets. Our experiments are motivated by our involvement in observations of molecules in space using radio telescopes.
The role of icy dust grains in interstellar chemistry:
The interstellar medium is full of microscopic dust grains made of silicates and carbon. In cold regions of space, these dust grains are covered in ices where simple molecules like molecular hydrogen and water, as well as more complex organic molecules (defined by astrochemists as >6 atoms) are formed. Yet many regions of interstellar space are so cold that it is puzzling how complex organic molecules can form when their precursors are essentially frozen on the ice surface and cannot react efficiently. To add to this puzzle, it is not understood how these molecules evaporate to the gas phase, where they can be detected by radio telescopes.
We build and use ultrahigh vacuum surface science experiments to investigate the efficiency of key processes involved in the formation and destruction of complex organic molecules on interstellar ices. We are currently interested in:
- The diffusion of astrophysically relevant radicals on ice surfaces
- Non-thermal diffusion via hot-atom and tunnelling mechanisms
- Non-thermal desorption mechanisms
- The production and reactivity of aromatic molecules in ices
- Experimental technique development
We are also interested in providing experimental support for upcoming missions that will observe the icy universe such as JWST.
Constraining aromatic and carbon chemistry during star formation
As much as 25% of all interstellar carbon is thought to be locked up in large aromatic molecules. How these species are formed and whether they can survive the harsh conditions of interstellar space are major open questions.
We build new experiments to constrain formation and destruction pathways involving aromatic molecules and heterocycles in space. We are currently thinking about:
- Non-energetic and energetic pathways to aromatic molecules on the surface of icy dust grains
- The formation of aromatic/heterocyclic molecules in the gas phase and their reactivity with radicals
- The stability of aromatic molecules to vacuum ultra-violet radiation and other energetic sources
The Cooke group is involved in a large collaboration called GOTHAM (GBT Observations of TMC-1, Hunting for Aromatic Molecules). GOTHAM uses high-resolution radio astronomical observations to search for new molecules in the interstellar medium. Once new molecules are detected, we seek to understand how they formed and whether they survive to be delivered to newly forming solar systems.