Saturn: Composition and chemistry

Abstract

The chapter reviews our current knowledge of the molecular, elemental, and isotopic composition and atmospheric chemistry in Saturn 's shallow atmosphere, i.e., between the cloud levels and the homopause. We do not restrict the review to Cassini 's results, as past and current ground-based or Earth-based observations are still fundamental to draw a complete picture of the planet. We address the global composition and its importance in studying the origin of the planet, and the meridional and vertical gradients in composition, stressing their insights into Saturn 's dynamics. We present the current 1D thermochemical and photochemical models, how these models fare to reproduce the observed composition, and the first attempts to design 2D chemical models. We present some directions to improve our knowledge of Saturn 's composition both from observations, modelling and laboratory experiments. © 2009 Springer Science+Business Media B.V.