Jupiter atmospheric composition

The atmospheric composition of Jupiter is much different from tlx --< of Mars and Venus. It is similar to the primitive stellar atmospheres. I In... 

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. 

The first sacred cow to be sacrificed was the Jupiter-like composition of Earth s primordial atmosphere. In fact, life must have evolved under an atmosphere that contained very little methane, hydrogen or ammonia. The evidence for this is direct and comes from geology. 

Figure 3. Isotopic composition of various Xe components, normalized to Xe and the terrestrial atmospheric composition. Solar wind Xe (SW), U-Xe, and Xe in Jupiter s atmosphere are discussed in the Sun and Jupiter sections (Tables 5 and 7), the meteoritic component Xe-Q (Busemann et al. 2000) is discussed in the chapter by Ott (2002). Xe in Jupiter s atmosphere is probably heavier than terrestrial atmospherie Xe, and might be eonsistent with either of the other eompositions shown. Note that the absolute ordinate position of the Jupiter pattern depends heavily on the ehoiee of the normalisation isotope, as visualized by the error bar on the normalizing isotope Xe (cf. Mahaffy et al. 2000).

Figure 15. Jupiter atmospheric Xe composition measured by the Galileo Probe mass spectrometer (Mahaffy et al. 2000), calculated as the abundance of each isotope M divided by the total abundance for all M and plotted relative to the NEA-Xe composition (Table 1) represented in the same way. The five most abundant Jovian Xe isotopes are indicated by the shaded symbols. U-Xe, SW2-Xe, and AVCC-Xe compositions in Table 1 are shown for comparison in the same representation. The data indicate deficits at the two heaviest isotopes relative to NEA-Xe and AVCC-Xe, but uncertainties are too large to rule between SW-Xe and U-Xe as the Jovian composition.

Jupiter is the largest planet within the solar system (Fig. 3.14). Its mass is 2.5 times the mass of all other planets in the solar system. Jupiter s atmosphere is composed of about 88-92% of hydrogen and 8-12% of helium. There are also traces of carbon, ethane, hydrogen sulfide, neon, oxygen, methane, water vapor, ammonia, silicon-based compound and also phosphine and sulfur. Helium in the Jupiter atmosphere is depleted (compared with the composition of the primordial solar nebula). This can be explained by a precipitation of the helium into the interior of the planet. The composition of Saturn is similar to that of Jupiter, Uranus and Neptune have much less hydrogen and helium. 

The period of emergence of life on Earth is constrained to be between the period 4.0-3.7 Gyr ago, for which there is no fossil record. Urey postulated that all of the planets formed from the same solar nebula and so the early Earth should have an atmosphere with a composition the same as that of Jupiter (known at the time),... 

Aspects of the chemical composition of the atmospheres of Jupiter, Saturn, Uranus, and Neptune were measured by the Voyager and Galileo spacecraft in the 1980s and 1990s,... 

Hydrogen isotopic compositions, expressed as molar D/H ratios, of solar system bodies. The relatively low D/H values in the atmospheres of Jupiter and Saturn are similar to those in the early Sun, whereas D/H ratios for Uranus and Neptune are intermediate between the Jupiter-Saturn values and those of comets and chondrites. The Earth s oceans have D/H shown by the horizontal line. Mars values are from SNC meteorites. Modified from Righter et al. (2006) and Lunine (2004). 

Table VIII-4. Chemical Composition of the Atmosphere" of Jupiter (735, 788, 943)... 

The necessary starting point for any study of the chemistry of a planetary atmosphere is the dissociation of molecules, which results from the absorption of solar ultraviolet radiation. This atmospheric chemistry must take into account not only the general characteristics of the atmosphere (constitution), but also its particular chemical constituents (composition). The absorption of solar radiation can be attributed to carbon dioxide (C02) for Mars and Venus, to molecular oxygen (02) for the Earth, and to methane (CH4) and ammonia (NH3) for Jupiter and the outer planets. 

A child on the planet Uranus would ask the question, Why is the sky green A child on Jupiter would ask the question, Why is the sky reddish brown How would you answer these questions Relate your answer to the chemical composition of the atmospheres of these planets. 

Jupiter and Uranus are outer planets composed mainly of gases. Jupiter s atmosphere contains reddish-brown clouds of ammonia. Uranus has an atmosphere made up mainly of hydrogen and helium with clouds of water vapor. This combination looks greenish to an outside observer. In addition, Mars has an atmosphere that is 95% carbon dioxide, and Venus has a permanent cloud cover of sulfur dioxide that appears pale yellow to an observer. Mercury has no permanent atmosphere. Saturn has 1 km thick dust and ice rings that orbit the planet. The eight planets in our solar system are diverse, each having different chemical compositions within and surrounding the planets. Out Earth is by far the friendliest planet for human existence. 

Figure 2.6 Carbon- and nitrogen-isotopic compositions of presolar SiC grains. Predictions from stellar models are shown for comparison. Solar metallicity AGB star models Nollett et al. (2003), Type II SN Rauscher et al. (2002), novae Jose et al. (2004). For data sources see Lodders Amari (2005) Zinner (2007). Note that for the solar 14N/15N ratio the value inferred for Jupiter s atmosphere is shown.

Carbon based chemistry (organic chemistry) has thus been established to be of fundamental importance in interstellar molecular clouds. Similarly the observed composition of comets is dominated by carbon bearing molecules, and in the reducing atmospheres of Jupiter and Saturn the carbon chain molecules C2H2, CjH have been detected. 

There are several comments on that. First of all, there is a path that somehow you have to follow in order to compare your results with existing ones. We only meant to change one parameter, the one that astrophysics was telling us we should change. As for your second remark a hypothetical atmosphere, well, it is hypothetical to a certain extent. There are in fact new data available for Jupiter and Titan. The composition used may be regarded as having been suggested by Titan. 

The temperature profiles within Jupiter and Saturn are thought to be essentially adiabatic, reflecting the high central temperatures and the dominant role of convection below the observable atmosphere where radiative processes become important. There may be deeper layers restricted in radial extent where the temperature profile becomes subadiabatic, due to a decrease in the total opacity, or by virtue of the behavior of the equation of state of hydrogen and helium. The same may hold for Uranus and Neptune, although with less certainty, because of the possibility that stable compositional gradients could exist and dominate the heat flow regime. In particular, Uranus small heat flow, if primordial and not a function of seasonal insolation, could be the result of a stable compositional stratification and hence subadiabatic temperature profile in the interior (Podolak et al., 1991). 

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