1
|
Buratti BJ, Orton GS, Roman MT, Momary T, Bauer JM. Astronomical Observations in Support of Planetary Entry-Probes to the Outer Planets. SPACE SCIENCE REVIEWS 2024; 220:46. [PMID: 38873000 PMCID: PMC11166823 DOI: 10.1007/s11214-024-01080-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 05/14/2024] [Indexed: 06/15/2024]
Abstract
A team of Earth-based astronomical observers supporting a giant planet entry-probe event substantially enhances the scientific return of the mission. An observers' team provides spatial and temporal context, additional spectral coverage and resolution, viewing geometries that are not available from the probe or the main spacecraft, tracking, supporting data in case of a failure, calibration benchmarks, and additional opportunities for education and outreach. The capabilities of the support program can be extended by utilizing archived data. The existence of a standing group of observers facilitates the path towards acquiring Director's Discretionary Time at major telescopes, if, for example, the probe's entry date moves. The benefits of a team convened for a probe release provides enhanced scientific return throughout the mission. Finally, the types of observations and the organization of the teams described in this paper could serve as a model for flight projects in general.
Collapse
Affiliation(s)
- Bonnie J. Buratti
- Jet Propulsion Laboratory California Institute of Technology, Pasadena, CA USA
| | - Glenn S. Orton
- Jet Propulsion Laboratory California Institute of Technology, Pasadena, CA USA
| | | | - Thomas Momary
- Jet Propulsion Laboratory California Institute of Technology, Pasadena, CA USA
| | | |
Collapse
|
2
|
Wong MH, Rowe-Gurney N, Markham S, Sayanagi KM. Multiple Probe Measurements at Uranus Motivated by Spatial Variability. SPACE SCIENCE REVIEWS 2024; 220:15. [PMID: 38343766 PMCID: PMC10858001 DOI: 10.1007/s11214-024-01050-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 01/18/2024] [Indexed: 02/22/2024]
Abstract
A major motivation for multiple atmospheric probe measurements at Uranus is the understanding of dynamic processes that create and maintain spatial variation in thermal structure, composition, and horizontal winds. But origin questions-regarding the planet's formation and evolution, and conditions in the protoplanetary disk-are also major science drivers for multiprobe exploration. Spatial variation in thermal structure reveals how the atmosphere transports heat from the interior, and measuring compositional variability in the atmosphere is key to ultimately gaining an understanding of the bulk abundances of several heavy elements. We review the current knowledge of spatial variability in Uranus' atmosphere, and we outline how multiple probe exploration would advance our understanding of this variability. The other giant planets are discussed, both to connect multiprobe exploration of those atmospheres to open questions at Uranus, and to demonstrate how multiprobe exploration of Uranus itself is motivated by lessons learned about the spatial variation at Jupiter, Saturn, and Neptune. We outline the measurements of highest value from miniature secondary probes (which would complement more detailed investigation by a larger flagship probe), and present the path toward overcoming current challenges and uncertainties in areas including mission design, cost, trajectory, instrument maturity, power, and timeline.
Collapse
Affiliation(s)
- Michael H. Wong
- Center for Integrative Planetary Science, University of California, Berkeley, CA 94720-3411 USA
- Carl Sagan Center for Science, SETI Institute, Mountain View, CA 94043-5232 USA
| | - Naomi Rowe-Gurney
- NASA Goddard Space Flight Center, Greenbelt, MD 20771 USA
- University of Maryland, College Park, MD 20742 USA
- The Center for Research and Exploration in Space Science & Technology (CRESST II), Greenbelt, MD 20771 USA
- The Royal Astronomical Society, Piccadilly, London, W1J 0BD UK
| | - Stephen Markham
- Observatoire de la Côte d’Azur, 06300 Nice, France
- Department of Astronomy, New Mexico State University, Las Cruces, NM 88003 USA
| | | |
Collapse
|
3
|
Ulenikov ON, Bekhtereva ES, Gromova OV, Fomchenko AL, Nikolaeva NI, Glushkov PA, Bauerecker S. On the method and results of calculation of vibrational tetrahedral sub-level energies and resonance interactions in vibrational spectra of high symmetry molecules: CH 4 and GeH 4 as an application of the XY 4 (T d) molecule. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023; 284:121796. [PMID: 36095857 DOI: 10.1016/j.saa.2022.121796] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 08/22/2022] [Accepted: 08/25/2022] [Indexed: 06/15/2023]
Abstract
We report here the analytical description of one of the important problems in the study of XY4 (Td) molecules, namely, description of vibrational tetrahedral sub-level structures and resonance interactions caused by the high symmetry of a molecule. The results obtained are applied to description of the vibrational energy spectrum of the CH4 and GeH4 molecules.
Collapse
Affiliation(s)
- O N Ulenikov
- Research School of High-Energy Physics, National Research Tomsk Polytechnic University, Tomsk, 634050, Russia.
| | - E S Bekhtereva
- Research School of High-Energy Physics, National Research Tomsk Polytechnic University, Tomsk, 634050, Russia
| | - O V Gromova
- Research School of High-Energy Physics, National Research Tomsk Polytechnic University, Tomsk, 634050, Russia
| | - A L Fomchenko
- Research School of High-Energy Physics, National Research Tomsk Polytechnic University, Tomsk, 634050, Russia
| | - N I Nikolaeva
- Research School of High-Energy Physics, National Research Tomsk Polytechnic University, Tomsk, 634050, Russia
| | - P A Glushkov
- Research School of High-Energy Physics, National Research Tomsk Polytechnic University, Tomsk, 634050, Russia
| | - S Bauerecker
- Institut fur Physikalische und Theoretische Chemie, Technische Universitat Braunschweig, D - 38106, Braunschweig, Germany
| |
Collapse
|
4
|
Bolton SJ, Adriani A, Adumitroaie V, Allison M, Anderson J, Atreya S, Bloxham J, Brown S, Connerney JEP, DeJong E, Folkner W, Gautier D, Grassi D, Gulkis S, Guillot T, Hansen C, Hubbard WB, Iess L, Ingersoll A, Janssen M, Jorgensen J, Kaspi Y, Levin SM, Li C, Lunine J, Miguel Y, Mura A, Orton G, Owen T, Ravine M, Smith E, Steffes P, Stone E, Stevenson D, Thorne R, Waite J, Durante D, Ebert RW, Greathouse TK, Hue V, Parisi M, Szalay JR, Wilson R. Jupiter's interior and deep atmosphere: The initial pole-to-pole passes with the Juno spacecraft. Science 2018; 356:821-825. [PMID: 28546206 DOI: 10.1126/science.aal2108] [Citation(s) in RCA: 186] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 05/01/2017] [Indexed: 11/02/2022]
Abstract
On 27 August 2016, the Juno spacecraft acquired science observations of Jupiter, passing less than 5000 kilometers above the equatorial cloud tops. Images of Jupiter's poles show a chaotic scene, unlike Saturn's poles. Microwave sounding reveals weather features at pressures deeper than 100 bars, dominated by an ammonia-rich, narrow low-latitude plume resembling a deeper, wider version of Earth's Hadley cell. Near-infrared mapping reveals the relative humidity within prominent downwelling regions. Juno's measured gravity field differs substantially from the last available estimate and is one order of magnitude more precise. This has implications for the distribution of heavy elements in the interior, including the existence and mass of Jupiter's core. The observed magnetic field exhibits smaller spatial variations than expected, indicative of a rich harmonic content.
Collapse
Affiliation(s)
- S J Bolton
- Southwest Research Institute, San Antonio, TX 78238, USA.
| | - A Adriani
- Institute for Space Astrophysics and Planetology, National Institute for Astrophysics, 00133 Rome, Italy
| | - V Adumitroaie
- Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109, USA
| | - M Allison
- Goddard Institute for Space Studies, New York, NY 10025, USA
| | - J Anderson
- Southwest Research Institute, San Antonio, TX 78238, USA
| | - S Atreya
- University of Michigan, Ann Arbor, MI 48109, USA
| | - J Bloxham
- Harvard University, Cambridge, MA 02138, USA
| | - S Brown
- Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109, USA
| | - J E P Connerney
- Space Research Corporation, Annapolis, MD 21403, USA.,NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
| | - E DeJong
- Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109, USA
| | - W Folkner
- Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109, USA
| | - D Gautier
- Laboratoire d'Études Spatiales et d'Instrumentation en Astrophysique, Observatoire de Paris, 92195 Meudon, France
| | - D Grassi
- Institute for Space Astrophysics and Planetology, National Institute for Astrophysics, 00133 Rome, Italy
| | - S Gulkis
- Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109, USA
| | - T Guillot
- Université Côte d'Azur, Observatoire de la Côte d'Azur, Laboratoire Lagrange CNRS, 06304 Nice, France
| | - C Hansen
- Planetary Science Institute, Tucson, AZ 85719, USA
| | - W B Hubbard
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA
| | - L Iess
- Sapienza University of Rome, 00185 Rome, Italy
| | - A Ingersoll
- California Institute of Technology, Pasadena, CA 91125, USA
| | - M Janssen
- Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109, USA
| | - J Jorgensen
- National Space Institute, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Y Kaspi
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - S M Levin
- Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109, USA
| | - C Li
- California Institute of Technology, Pasadena, CA 91125, USA
| | - J Lunine
- Cornell University, Ithaca, NY 14853, USA
| | - Y Miguel
- Université Côte d'Azur, Observatoire de la Côte d'Azur, Laboratoire Lagrange CNRS, 06304 Nice, France
| | - A Mura
- Institute for Space Astrophysics and Planetology, National Institute for Astrophysics, 00133 Rome, Italy
| | - G Orton
- Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109, USA
| | - T Owen
- Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - M Ravine
- Malin Space Science Systems, San Diego, CA 92121, USA
| | - E Smith
- Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109, USA
| | - P Steffes
- Center for Space Technology and Research, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - E Stone
- California Institute of Technology, Pasadena, CA 91125, USA
| | - D Stevenson
- California Institute of Technology, Pasadena, CA 91125, USA
| | - R Thorne
- Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, CA 90095, USA
| | - J Waite
- Southwest Research Institute, San Antonio, TX 78238, USA
| | - D Durante
- Sapienza University of Rome, 00185 Rome, Italy
| | - R W Ebert
- Southwest Research Institute, San Antonio, TX 78238, USA
| | - T K Greathouse
- Southwest Research Institute, San Antonio, TX 78238, USA
| | - V Hue
- Southwest Research Institute, San Antonio, TX 78238, USA
| | - M Parisi
- Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109, USA
| | - J R Szalay
- Southwest Research Institute, San Antonio, TX 78238, USA
| | - R Wilson
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303, USA
| |
Collapse
|
5
|
Ingersoll AP, Adumitroaie V, Allison MD, Atreya S, Bellotti AA, Bolton SJ, Brown ST, Gulkis S, Janssen MA, Levin SM, Li C, Li L, Lunine JI, Orton GS, Oyafuso FA, Steffes PG. Implications of the ammonia distribution on Jupiter from 1 to 100 bars as measured by the Juno microwave radiometer. GEOPHYSICAL RESEARCH LETTERS 2017; 44:7676-7685. [PMID: 33100420 DOI: 10.1002/2017gl073159] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The latitude-altitude map of ammonia mixing ratio shows an ammonia-rich zone at 0-5°N, with mixing ratios of 320-340 ppm, extending from 40-60 bars up to the ammonia cloud base at 0.7 bars. Ammonia-poor air occupies a belt from 5-20°N. We argue that downdrafts as well as updrafts are needed in the 0-5°N zone to balance the upward ammonia flux. Outside the 0-20°N region, the belt-zone signature is weaker. At latitudes out to ±40°, there is an ammonia-rich layer from cloud base down to 2 bars which we argue is caused by falling precipitation. Below, there is an ammonia-poor layer with a minimum at 6 bars. Unanswered questions include how the ammonia-poor layer is maintained, why the belt-zone structure is barely evident in the ammonia distribution outside 0-20°N, and how the internal heat is transported through the ammonia-poor layer to the ammonia cloud base.
Collapse
Affiliation(s)
- Andrew P Ingersoll
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
| | - Virgil Adumitroaie
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | | | - Sushil Atreya
- Climate and Space Sciences, University of Michigan, Ann Arbor, MI 48109, USA
| | - Amadeo A Bellotti
- Center for Space Technology and Research, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Scott J Bolton
- Southwest Research Institute, San Antonio, TX 78238, USA
| | - Shannon T Brown
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Samuel Gulkis
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Michael A Janssen
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Steven M Levin
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Cheng Li
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Liming Li
- Department of Physics, University of Houston, Houston, TX 77004, USA
| | | | - Glenn S Orton
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Fabiano A Oyafuso
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Paul G Steffes
- Center for Space Technology and Research, Georgia Institute of Technology, Atlanta, GA 30332, USA
| |
Collapse
|
6
|
Moses JI, Visscher C, Keane TC, Sperier A. On the abundance of non-cometary HCN on Jupiter. Faraday Discuss 2011; 147:103-36; discussion 251-82. [PMID: 21302544 DOI: 10.1039/c003954c] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Using one-dimensional thermochemical/photochemical kinetics and transport models, we examine the chemistry of nitrogen-bearing species in the Jovian troposphere in an attempt to explain the low observational upper limit for HCN. We track the dominant mechanisms for interconversion of N2-NH3 and HCN-NH3 in the deep, high-temperature troposphere and predict the rate-limiting step for the quenching of HCN at cooler tropospheric altitudes. Consistent with some other investigations that were based solely on time-scale arguments, our models suggest that transport-induced quenching of thermochemically derived HCN leads to very small predicted mole fractions of hydrogen cyanide in Jupiter's upper troposphere. By the same token, photochemical production of HCN is ineffective in Jupiter's troposphere: CH4-NH3 coupling is inhibited by the physical separation of the CH4 photolysis region in the upper stratosphere from the NH3 photolysis and condensation region in the troposphere, and C2H2-NH3 coupling is inhibited by the low tropospheric abundance of C2H2. The upper limits from infrared and submillimetre observations can be used to place constraints on the production of HCN and other species from lightning and thundershock sources.
Collapse
Affiliation(s)
- Julianne I Moses
- Space Science Institute, 1602 Old Orchard Ln, Seabrook, TX 77586, USA.
| | | | | | | |
Collapse
|
7
|
Affiliation(s)
- Adam P. Showman
- National Research Council (NRC)/NASA Ames Research Center, Mail Stop 245-3, Moffett Field, CA 94035–1000, USA
| | - Timothy E. Dowling
- Comparative Planetology Laboratory, University of Louisville, 211 Sackett Hall, Louisville, KY 40292, USA
| |
Collapse
|
8
|
Mahaffy PR, Niemann HB, Alpert A, Atreya SK, Demick J, Donahue TM, Harpold DN, Owen TC. Noble gas abundance and isotope ratios in the atmosphere of Jupiter from the Galileo Probe Mass Spectrometer. ACTA ACUST UNITED AC 2000. [DOI: 10.1029/1999je001224] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
9
|
Moist convection as an energy source for the large-scale motions in Jupiter's atmosphere. Galileo Imaging Team. Nature 2000; 403:630-2. [PMID: 10688192 DOI: 10.1038/35001021] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Jupiter's dominant large-scale weather patterns (dimensions approximately 10,000 km) are zonal jets and long-lived ovals. The jets have been flowing east and west at constant speeds of up to 180 m s(-1) for over 100 years. These jets receive energy from small-scale eddies, which pump eastward momentum into the eastward jets and westward momentum into the westward jets. This momentum transfer was predicted by numerical models before it was observed on Jupiter. The large ovals roll between the jets in an anticyclonic direction-clockwise in the northern hemisphere and counterclockwise in the southern hemisphere--where they regularly assimilate small anticyclonic eddies. But from where the eddies receive their energy has been an open question. Here we argue that the eddies, which ultimately drive both the jets and the ovals, receive their energy from moist convection. This hypothesis is consistent with observations of jovian lightning, which is an indicator of moist convection. It also explains the anticyclonic rotation and poleward drift of the eddies, and suggests patterns of upwelling and downwelling that resemble the patterns of large-scale axisymmetric overturning in the Earth's atmosphere.
Collapse
|
10
|
Owen T, Mahaffy P, Niemann HB, Atreya S, Donahue T, Bar-Nun A, de Pater I. A low-temperature origin for the planetesimals that formed Jupiter. Nature 1999; 402:269-70. [PMID: 10580497 DOI: 10.1038/46232] [Citation(s) in RCA: 248] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The four giant planets in the Solar System have abundances of 'metals' (elements heavier than helium), relative to hydrogen, that are much higher than observed in the Sun. In order to explain this, all models for the formation of these planets rely on an influx of solid planetesimals. It is generally assumed that these planetesimals were similar, if not identical, to the comets from the Oort cloud that we see today. Comets that formed in the region of the giant planets should not have contained much neon, argon and nitrogen, because the temperatures were too high for these volatile gases to be trapped effectively in ice. This means that the abundances of those elements on the giant planets should be approximately solar. Here we show that argon, krypton and xenon in Jupiter's atmosphere are enriched to the same extent as the other heavy elements, which suggests that the planetesimals carrying these elements must have formed at temperatures lower than predicted by present models of giant-planet formation.
Collapse
Affiliation(s)
- T Owen
- University of Hawaii, Institute for Astronomy, Honolulu 96822, USA.
| | | | | | | | | | | | | |
Collapse
|
11
|
Atreya SK, Wong MH, Owen TC, Mahaffy PR, Niemann HB, de Pater I, Drossart P, Encrenaz TH. A comparison of the atmospheres of Jupiter and Saturn: deep atmospheric composition, cloud structure, vertical mixing, and origin. PLANETARY AND SPACE SCIENCE 1999; 47:1243-1262. [PMID: 11543193 DOI: 10.1016/s0032-0633(99)00047-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We present our current understanding of the composition, vertical mixing, cloud structure and the origin of the atmospheres of Jupiter and Saturn. Available observations point to a much more vigorous vertical mixing in Saturn's middle-upper atmosphere than in Jupiter's. The nearly cloud-free nature of the Galileo probe entry site, a 5-micron hotspot, is consistent with the depletion of condensable volatiles to great depths, which is attributed to local meteorology. Somewhat similar depletion of water may be present in the 5-micron bright regions of Saturn also. The supersolar abundances of heavy elements, particularly C and S in Jupiter's atmosphere and C in Saturn's, as well as the progressive increase of C from Jupiter to Saturn and beyond, tend to support the icy planetesimal model of the formation of the giant planets and their atmospheres. However, much work remains to be done, especially in the area of laboratory studies, including identification of possible new microwave absorbers, and modelling, in order to resolve the controversy surrounding the large discrepancy between Jupiter's global ammonia abundance, hence the nitrogen elemental ratio, derived from the earth-based microwave observations and that inferred from the analysis of the Galileo probe-orbiter radio attenuation data for the hotspot. We look forward to the observations from Cassini-Huygens spacecraft which are expected to result not only in a rich harvest of information for Saturn, but a better understanding of the formation of the giant planets and their atmospheres when these data are combined with those that exist for Jupiter.
Collapse
Affiliation(s)
- S K Atreya
- Department of Atmospheric, Oceanic and Space Sciences, The University of Michigan, Ann Arbor 48109-2143, USA.
| | | | | | | | | | | | | | | |
Collapse
|
12
|
Niemann HB, Atreya SK, Carignan GR, Donahue TM, Haberman JA, Harpold DN, Hartle RE, Hunten DM, Kasprzak WT, Mahaffy PR, Owen TC, Way SH. The composition of the Jovian atmosphere as determined by the Galileo probe mass spectrometer. JOURNAL OF GEOPHYSICAL RESEARCH 1998; 103:22831-45. [PMID: 11543372 DOI: 10.1029/98je01050] [Citation(s) in RCA: 266] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The Galileo probe mass spectrometer determined the composition of the Jovian atmosphere for species with masses between 2 and 150 amu from 0.5 to 21.1 bars. This paper presents the results of analysis of some of the constituents detected: H2, He, Ne, Ar, Kr, Xe, CH4, NH3, H2O, H2S, C2 and C3 nonmethane hydrocarbons, and possibly PH3 and Cl. 4He/H2 in the Jovian atmosphere was measured to be 0.157 +/- 0.030. 13C/C12 was found to be 0.0108 +/- 0.0005, and D/H and 3He/4He were measured. Ne was depleted, < or = 0.13 times solar, Ar < or = 1.7 solar, Kr < or = 5 solar, and Xe < or = 5 solar. CH4 has a constant mixing ratio of (2.1 +/- 0.4) x 10(-3) (12C, 2.9 solar), where the mixing ratio is relative to H2. Upper limits to the H2O mixing ratio rose from 8 x 10(-7) at pressures <3.8 bars to (5.6 +/- 2.5) x 10(-5) (16O, 0.033 +/- 0.015 solar) at 11.7 bars and, provisionally, about an order of magnitude larger at 18.7 bars. The mixing ratio of H2S was <10(-6) at pressures less than 3.8 bars but rose from about 0.7 x 10(-5) at 8.7 bars to about 7.7 x 10(-5) (32S, 2.5 solar) above 15 bars. Only very large upper limits to the NH3 mixing ratio have been set at present. If PH3 and Cl were present, their mixing ratios also increased with pressure. Species were detected at mass peaks appropriate for C2 and C3 hydrocarbons. It is not yet clear which of these were atmospheric constituents and which were instrumentally generated. These measurements imply (1) fractionation of 4He, (2) a local, altitude-dependent depletion of condensables, probably because the probe entered the descending arm of a circulation cell, (3) that icy planetesimals made significant contributions to the volatile inventory, and (4) a moderate decrease in D/H but no detectable change in (D + 3He)/H in this part of the galaxy during the past 4.6 Gyr.
Collapse
Affiliation(s)
- H B Niemann
- Goddard Space Flight Center, Greenbelt, Maryland, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Ragent B, Colburn DS, Rages KA, Knight TCD, Avrin P, Orton GS, Yanamandra-Fisher PA, Grams GW. The clouds of Jupiter: Results of the Galileo Jupiter Mission Probe Nephelometer Experiment. ACTA ACUST UNITED AC 1998. [DOI: 10.1029/98je00353] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
14
|
|
15
|
Orton GS, Fisher BM, Baines KH, Stewart ST, Friedson AJ, Ortiz JL, Marinova M, Ressler M, Dayal A, Hoffmann W, Hora J, Hinkley S, Krishnan V, Masanovic M, Tesic J, Tziolas A, Parija KC. Characteristics of the Galileo probe entry site from Earth-based remote sensing observations. ACTA ACUST UNITED AC 1998. [DOI: 10.1029/98je02380] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
16
|
Seiff A, Kirk DB, Knight TCD, Young RE, Mihalov JD, Young LA, Milos FS, Schubert G, Blanchard RC, Atkinson D. Thermal structure of Jupiter's atmosphere near the edge of a 5-μm hot spot in the north equatorial belt. ACTA ACUST UNITED AC 1998. [DOI: 10.1029/98je01766] [Citation(s) in RCA: 250] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
17
|
Sromovsky LA, Collard AD, Fry PM, Orton GS, Lemmon MT, Tomasko MG, Freedman RS. Galileo probe measurements of thermal and solar radiation fluxes in the Jovian atmosphere. ACTA ACUST UNITED AC 1998. [DOI: 10.1029/98je01048] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|