Prebiotic polymers., infrared spectra of galactic sources.

Prebiotic polymers are among the infrared absorption features characteristic of molecular dust clouds. Although the chemical composition of interstellar dust is uncertain, it is suggested that (1) grains of silicates, iron, and graphite are produced in cool stars, (2) there may be a dominance of a dielectric grain material at optical wavelengths, and (3) a large amount of grain material may be composed of C, N, and O elements which combine with hydrogen and exist as molecular mantles on grains. Infrared absorption features have been observed in galactic sources including bands centered on 3.1, 3.4, 8-12 and approximately 20 microns. It is noted that organic polymers (rather than silicate grains) may provide an explanation of astronomical absorption spectra at near and mid-infrared wavelengths. A complex organic or prebiotic polymer could have absorption properties similar to those of the synthetic polymer spectrum. A stable polymer of this type is sporopollenin which may be similar to the prebiological polymers associated with interstellar grains.