Jupiter's Spectrum Between 12 and 24 Micrometers

Abstract

Spectroscopic measurements of the thermal radiation from Jupiter between 12 and 24 micrometers (420 to 840 reciprocal centimeters) with a resolution of 4 reciprocal centimeters are used to infer the Jovian temperature structure in the pressure region 0.1 to 0.4 atmosphere. The brightness temperature spectrum is in good agreement with previous ground-based measurements between 11 and 13 micrometers and with airborne measurements between 18 and 25 micrometers. However, the integrated flux calculated for a filter window and viewing angle equivalent to those of the 20 micrometer channel of Pioneer 10 is 20 percent below that measured by the Pioneer infrared radiometer. The Q branch of the v₅ fundamental band of acetylene at 730 reciprocal centimeters appears in emission and leads to a mixing ratio estimate of 10^{–6 ± 0.5}.