“Detection of a branched alkyl molecule in the interstellar medium: iso-propyl cyanide”
My research program is focused on astrochemistry and astrobiology. Themes include the production of complex organic molecules in the interstellar medium and star forming regions, the formation and evolution of dust-grain ice mantles in such environments, and the coupling between gas-phase and grain-surface processes.
I construct computer models that simulate the gas-phase and dust-grain surface/ice-mantle chemical kinetics occurring in the ISM (interstellar medium). I also use the results of these models to simulate sub-mm and mm-band observations of star-forming regions known as hot cores, in which are found the most complex molecules yet detected in the ISM. I am a member of some collaborative observing projects of such regions, including ALMA observations toward the richest hot-core source, Sgr B2(N) (with collaborators at the Max Planck Institute for Radioastronomy and Univ. of Cologne, Germany).
I recently investigated the possible formation of the simplest amino acid, glycine (NH2CH2COOH), in star-forming regions, and assessed its putative detectability by simulating the emission from all molecules within a specific nearby source.
I have used similar chemical models to explain the formation (at varying visual extinctions) of the abundant interstellar ice constituents H2O, CO and CO2, and to explain the existence of polar and apolar signatures for these ices.
Recently, I have developed a new Monte Carlo grain-surface chemistry code that traces the precise positions of each surface species, allowing the structure of the ice mantle to be explicitly simulated (and to produce time-lapse 3-D videos of this process).
I am currently using experimental UV ice-processing results (from Univ. of Leiden, Netherlands; Oberg et al. 2009) to fit the full parameter-space of an ice chemical kinetics model, which may then be directly applied to interstellar conditions.
I am extending my interstellar ice chemical models to cometary ices, to investigate the degree of processing that they undergo throughout their lifetimes: from the “cold storage” phase within the Oort cloud and/or Kuiper Belt/extended disk, to their active phase. This will determine the production and destruction of complex organics in the outer layer of the comet, and the potential for delivery of biologically-relevant molecules to the early Earth.
More details of each of my active research topics may be found by clicking below: