Planets atmospheric composition

In Earth s upper atmosphere (and, in planetary probe missions, the atmospheres of other planets), atmospheric composition can be measured in situ with mass spectrometers and related instrumentation. However, UV measurements provide a capability for remote sensing of atmospheric composition and its variation with altitude, geographic location, and time, which supplements and extends in situ measurements where available, and can be applied to many objects not yet visited by spacecraft (e.g., in observations of other planets by spacecraft in near-Earth orbit). In addition to atmospheric composition, UV measurements can remotely sense the atmospheric temperature structure and its spatial and temporal variations. Also, information on the fluxes, energies, and spatial distributions of incoming energetic particles (such as those that produce Earth s polar auroras) can be obtained. 

However, we need information on the atmospheric composition in order to plan and carry out simulation experiments. Although the four terrestrial planets originated from the same solar matter, their atmospheres are completely different. This is due to ... 

Estimated compositions ofthe giant planets are given in Table 14.3, normalized to the solar composition. The relative proportions of rock and volatiles are estimated from mean densities, the rock compositions are assumed to be chondritic, and the ratios of hydrogen to helium are derived from spectroscopic or spacecraft measurements of atmosphere compositions. 

Pepin R. O. (2000) On the isotopic composition of primordial xenon in terrestrial planet atmospheres. Space Sci. Rev. 92, 371-395. 

Atreya S. K., Wong M. H., Owen T. C., Mahaffy P. R., Niemann H. B., de Pater I., Drossart P., and Encrenaz Th. (1999b) A comparison of the atmospheres of Jupiter and Saturn deep atmospheric composition, cloud structure, vertical mixing, and origin. Planet. Space Sci. 47, 1243-1262. 

Planet Satellites Surface composition (including condensed trapped species) Atmospheric composition... 

Mars. The combination of Viking in situ measurements and SNC meteorite data has provided a much more quantitative view of the present state and possible history of martian volatiles. Further progress requires greater precision for the atmospheric composition, more data on possible near-surface and mantle reservoirs, and further constraints on the conditions that affect the volatile evolution of all the terrestrial planets. 

The interior and atmospheric composition of the Jovian planets and Titan differ from our terrestrial planets in particular, Jovian planets and Titan contain complex organic solids named tholins [152]. Sagan et al. [153] diermochemically... 

Mass spectrometers have even made it into space, where modified GC-MS equipment has been installed in space probes to measure the atmospheric composition of distant planets and their moons. 

Irwin, Patrick. Giant Planets of Our Solar System Atmospheres, Composition, and Structure. New York Springer Verlag, 2003. 

It can clearly be seen from Table 1 that the Earth s atmosphere consists mainly of nitrogen and oxygen. However, this composition, which makes the present life on our planet possible, cannot be considered normal in the solar system. Thus, even the nearest planets like Mars and Venus have a very different atmospheric composition. 

Chemical equilibrium abundances for many C-, N-, and 0-bearing gases for T = 500-2500K and P = 10" -1000 bars for a solar composition gas can be found in 54). Although these calculations were applied to brown dwarfs and giant planet atmospheres, the pressure conditions also include those appropriate for O-rich photospheres and their inner CSEs (10" - 10" bars). 

If this is the case, atmospheric compositions on Venus are enormously important in the context of models for the origin and evolution of terrestrial planet volatiles, particular in the case of Xe. The general similarity of nonradiogenic Xe isotope ratios on Earth and Mars is the strongest argument in favor of the fractionation of Xe on common pre-planetary carriers rather than on the planets themselves, although the correspondence does not appear to be exact. The ability of Venusian Xe to rule between the predictions of... 

Patterson DB, Farley KA, Mclnnes BIA (1997) Helinm isotopic composition of the Tabar-Lihir-Tanga-Feni island arc, Papna New Gninea. Geochim Cosmochim Acta 61 2485-2496 Pedroni A, Hammerschmidt K, Friedrichsen H (1999) He, Ne, Ar, and C isotope systematics of geothermal emanations in the Lesser Antilles Islands Arc. Geochim Cosmochim Acta 63 515-532 Pepin RO (1991) On the origin and early evolntion of terrestrial planet atmospheres and meteoritic values. Icaras 92 1-79... 

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