The infrared spectra of dense molecular clouds provide evidence that the ices in these interstellar enviornments are often processed by ionizing radiation. In the Astrochemistry Laboratory we carry out laboratory simulations of this processing on analog materials using a variety of sophisticated instruments. These studies have demonstrated that the UV irradiation of even very simple ices can result in the production of refractory organic residues that contain complicated mixtures of more complex organic molecules. Some of these new molecules have properties that are of prebiotic interest.

One of the more interesting results of this work is shown below. When our organic residues are placed in water, one or more of the compounds present spontaneously form membranes that produce 'vesicles' of the sort shown below.

The top image shows what the vesicles look like in visibly light. Interestingly, the membranes in these structures fluoresce, that is, they absorb UV radiation and re-emit the energy at visible wavelengths. The lower image shows the same field as the upper image, the difference being that in the lower image, the sample is being illuminated by UV light and the vesicles are 'glowing.'

For more information on these residues and the membranes they produce, see an article of ours that appeared in a chapter in a book on the Origin of Life and an article in The New Scientist. Additional information on our work in the area of astrobiology and the origin of life can be found here.

For more detailed information on our laboratory work on the organics produced by the UV irradiation of astrophysical ices, see:

Bernstein, M. P., Sandford, S. A., Allamandola, L. J., Gillette, J. S., Clemett, S. J., & Zare, R. N. (1999). UV Irradiation of Polycyclic Aromatic Hydrocarbons in Ices: Production of Alcohols, Quinones, and Ethers. Science 283, 1135-1138.

Allamandola, L. J., Bernstein, M. P., & Sandford, S. A. (1997). Photochemical evolution of interstellar/precometary organic material. In Astronomical and Biochemical Origins and the Search for Life in the Universe, C.B. Cosmovici, S. Bowyer, & D. Werthimer (eds.), Proc. 5th International Conf. on Bioastronomy, IAU Coll. #161, Capri, 1-5 July 1996, (Editrice Compositori: Bologna), pp. 23-47.

Bernstein, M. P., Sandford, S. A., Allamandola, L. J., Chang, S., & Scharberg, M. A. (1995). Organic Compounds Produced by Photolysis of Realistic Interstellar and Cometary Ice Analogs Containing Methanol. Astrophys. J. 454, 327-344.

Allamandola, L. J., Sandford, S. A., & Valero, G. (1988). Photochemical and thermal evolution of interstellar/pre-cometary ice analogs. Icarus 76, 225-252.