Microwave Measurements of Carbon Monoxide on Titan

The ratio of the flux density of Titan was measured in two 200-megahertz bands, one centered on the (1-0) rotation line of carbon monoxide at 115.3 gigahertz and the other 2600 megahertz lower. The measurements were made with a complex-correlation technique on the new millimeter-wavelength interferometer at the Owens Valley Radio Observatory, Big Pine, California. The excess flux in the carbon monoxide band is interpreted as a strong detection of carbon monoxide and a mixing ratio, assumed constant, of 6 x 10(-5). The brightness temperature of Titan at 112.6 gigahertz is 69 +/- 10 kelvins, consistent with atmospheric emission from just below the tropopause.