Formation Of The Giant Planets And Their Atmospheres: A Case For Multiprobe Exploration
- Paper number
IAC-07-A3.4.06
- Author
Prof. Sushil Atreya, University of Michigan, United States
- Year
2007
- Abstract
Comparative planetology of the giant planets is key to the mystery of the formation of the solar system, and by extension the extrasolar systems. According to conventional models, grains of dust, ice, metals and refractory material first formed a core. Once the core reached a critical mass, 10-15 Earth Mass for Jupiter, gravitational capture of the most volatile of gases (H, He, Ne) occurred, leading to the collapse of the surrounding protoplanetary nebula. This constrains their elemental composition to solar. However, the Galileo probe revealed that the heavy elements, C, N, S, Ar, Kr, and Xe all enriched relative to solar (ratioed to solar). This requires that the planet forming planetesimals be cold enough to trap nitrogen and argon, i.e. 30K, and delivered throughout the formation and later. The origin of such cold planetesimals – icy, or clathrates – is unknown. One key piece of information that could help but is still missing is the abundance of water in the well-mixed atmosphere of Jupiter, since the Galileo probe entered a dry spot of Jupiter. Microwave radiometry observations from the 2011 Juno mission are expected to determine the well-mixed water abundance. At Saturn, heavy element data, except on carbon is missing. Probes are needed. They alone, not remote sensing, can determine the heavy element abundance – C, N, S, O, Ar, Kr, Xe – together with He, noble gas isotopes, D/H, and 15N/14N, which are required to constrain the models of the formation of Saturn and its atmosphere. Probes into Neptune and Uranus will be essential also for such critical data. [email: <atreya@umich.edu> webpage for downloading pdf's: <http://umich.edu/~atreya/>]
- Abstract document
- Manuscript document
IAC-07-A3.4.06.pdf (🔒 authorized access only).
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