First Spitzer observations of Neptune:: Detection of new hydrocarbons

We present the first spectra of Neptune taken with the Spitzer Space Telescope, highlighting the high-sensitivity, moderate-resolution 10-20 mu m (500-1000 cm(-1)) spectra. We report the discovery of methylacetylene (CH3C2H) and diacetylene (C4H2) with derived 0.1-mbar volume mixing ratios of (1.2 +/- 0.1) x 10(-10) and (3 +/- 1) X 10(-12) respectively. (C) 2008 Elsevier Inc. All rights reserved.