ISO observations of planetary atmospheres Original Research Article

The Infrared Space Observatory (ISO) satellite, operated by ESA in 1995–1998, has provided a very significant contribution to our knowledge of planetary atmospheres. The main results of ISO observations of the giant planets and Titan can be summarized as follows: (1) a new determination of the D/H ratio; (2) the discovery of an external source of water, and the detection of CO2 in the stratospheres of Saturn, Neptune and Jupiter; (3) the detection of new hydrocarbons in the stratospheres of Saturn (CH3C2H, C4H2, C6H6, CH3), Jupiter (CH3C2H, C6H6) and Neptune (CH3, C2H4); (4) the study of NH3 and PH3 in Jupiter and Saturn, and the determination of 14N/15N in Jupiter; (5) the detection of H2O in the deep troposphere of Saturn; (6) the observation of H3+ in Uranus. ISO spectra of Mars have provided information about the water vapor content and the composition of aerosols.