Program: GS-2005A-Q-24

We propose observations of the unique proto-planetary nebula, the Red Rectangle, and its central (binary) star HD 44179, in the near-UV/blue and far-red optical regions in order to identify the suspected medium/large sized aromatic polycyclic aromatic hydrocarbon (PAH) molecules formed in the nebula, and to determine the evolution of carbon-rich material from a near-stellar environment towards dust in the interstellar medium. The well-defined geometry of the nebula will allow correlations of the emission with previously recorded spatial distributions of (a) strong 3.3 micron and mid-IR UIR band emission attributed to PAHs, and (b) prominent optical emission bands that appear to be emission counterparts to some of the c. 300 unidentified diffuse interstellar absorption bands. The programme will contribute to resolving key astronomical questions including the identification of specific polycyclic aromatic hydrocarbon molecules, the optical properties of interstellar dust and the identity of the diffuse interstellar band carriers.