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| Titel |
Mass Spectrometry in Jupiter's Atmosphere: Vertical Variation of Volatile Vapors |
| VerfasserIn |
Michael H. Wong, Sushil K. Atreya, Paul R. Mahaffy |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250090258
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| Publikation (Nr.) |
 EGU/EGU2014-4480.pdf |
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| Zusammenfassung |
| The Galileo Probe made the first and only in situ measurements of composition in Jupiter’s
atmosphere, led by the Galileo Probe Mass Spectrometer, or GPMS [1]. The major
contribution from this instrument was the measurement of abundances and isotope ratios of
the noble gases, as well as the volatile gases CH4, NH3, H2O, and H2S [2,3]. These initial
results were further refined by detailed laboratory calibrations for the noble gases [4] and the
volatiles [5]. The probe measurements resulted in the first determination of the heavy element
abundances (except carbon that was known previously) and He/H ratio, which provide critical
constraints to models of the formation of Jupiter and the origin of its atmosphere
[6,7].
The condensable volatiles, or CVs (ammonia, H2S, and water), increased with depth in
the probe entry site. This vertical variation was observed at levels much deeper than
the modeled cloud bases, as predicted by one-dimensional chemical equilibrium
models. The discrepancy is due to the probe’s entry into a dry region known as a
5-μm hot spot. The 5-μm hot spots are part of an atmospheric wave system that
encircles Jupiter just north of the equator. Despite the anomalous meteorology, the bulk
abundances of NH3 and H2S were measured by the probe, and found to be enriched with
respect to solar composition (similarly to the non-condensable volatile CH4). The
deepest water mixing ratio, however, was observed to be depleted relative to solar
composition.
We review an updated context for the CV vertical profiles measured by the GPMS, based
on the latest results from remote sensing, simulation, and reinterpretation of Galileo Probe
measurements. In particular, we find that (1) the bulk abundance of water in Jupiter’s
atmosphere must be greater than the subsolar abundance derived from the deepest GPMS
measurements [8], and that (2) CV mixing ratios are controlled by a range of processes in
addition to condensation of the ices NH3, NH4SH, and H2O [5–9]. Both bulk abundances and
spatial variation of these species will be further constrained by the Juno mission, scheduled to
arrive at Jupiter in 2016.
References:
[1] Niemann, H.B.et al.1992, SSRv 60, 111–142
[2] Niemann, H.B.et al.1996, Science 272, 846–849
[3] Niemann, H.B.et al.1998, JGR 103, 22831–22845
[4] Mahaffy, P.R.et al.2000, JGR 105, 15061–15071
[5] Wong, M.H.et al.2004, Icarus 171, 153–170
[6] Atreya, S.K.et al., 1999, Planet.Space Sci.47, 1243–1262
[7] Atreya, S.K.et al., 2003, Planet.Space Sci.451, 105–112
[8] Wong, M.H.et al., 2008, in Reviews in Mineralogy and Geochemistry, vol. 68.
Mineralogical Society of America, Chantilly, VA, pp. 219–246
[9] Wong, M.H., 2009, Icarus 199, 231–235 |
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