Study of planetary atmospheres by absorptive occultations

摘要: As a spacecraft observes the setting or rising of Sun star behind limb planet, absorption spectrum upper atmosphere can be observed as function height. This powerful method give composition and vertical distribution individual gases, from which temperatures derived. review describes technique methods data reduction. Early experiments on Earth's (many sounding rockets) are briefly summarized; many them were compromised by need to use instruments not designed for purpose. Emphasis is placed observations other planets, ultraviolet spectrometers able look at well stars. Mariner 10 set tight limits Mercury (and also found tiny quantities H He). The Voyager defined atmospheres all four Jovian satellites Titan Triton. potential future measurements least rich history, especially platforms optimized