Gravity results from Pioneer 10 Doppler data
TL;DR: In this article, two-way Doppler data received from Pioneer 10 during its encounter with Jupiter have been analyzed, and preliminary results have been obtained on the mass and the gravity field of Jupiter and on the masses of the four Galilean satellites.
Abstract: Two-way Doppler data received from Pioneer 10 during its encounter with Jupiter have been analyzed, and preliminary results have been obtained on the mass and the gravity field of Jupiter and on the masses of the four Galilean satellites. The ratios of the masses of the satellites to the mass of Jupiter are approximately 0.00004696 for Io, 0.00002565 for Europa, 0.00007845 for Ganymede, and 0.00005603 for Callisto (all error estimates presented in this paper are standard errors; those for Pioneer 10 represent our evaluation of the real errors as distinguished from formal errors). The ratio of the mass of the sun to the mass of the Jupiter system is about 1047.342, which is in good agreement with recent determinations from the motions of asteroids. The second- and fourth-degree zonal harmonic coefficients in the gravity field of Jupiter are 0.014720 and -0.00065, respectively, based on an equatorial planetary radius of 71,400 km, and the derived dynamical oblateness is 0.0647 at the same radius. The Pioneer 10 data are consistent with the assumption that Jupiter is in hydrostatic equilibrium at all levels.
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University of Arizona1, United States Geological Survey2, Jet Propulsion Laboratory3, California Institute of Technology4, University College London5, RAND Corporation6, Smithsonian Astrophysical Observatory7, State University of New York System8, Cornell University9, New Mexico State University10, University of Hawaii11, NASA Headquarters12, University of Wisconsin-Madison13
TL;DR: The cameras aboard Voyager 1 have provided a closeup view of the Jupiter system, revealing heretofore unknown characteristics and phenomena associated with the planet's atmosphere and the surfaces of its five major satellites.
Abstract: The cameras aboard Voyager 1 have provided a closeup view of the Jupiter system, revealing heretofore unknown characteristics and phenomena associated with the planet's atmosphere and the surfaces of its five major satellites. On Jupiter itself, atmospheric motions-the interaction of cloud systems-display complex vorticity. On its dark side, lightning and auroras are observed. A ring was discovered surrounding Jupiter. The satellite surfaces display dramatic differences including extensive active volcanism on Io, complex tectonism on Ganymede and possibly Europa, and flattened remnants of enormous impact features on Callisto.
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01 Jan 1976TL;DR: In this paper, the origin and evolution of the solar system are analyzed, followed by experimental studies of plasma-solid reactions and chemical and mineralogical analyses of meteorites and lunar and terrestrial samples.
Abstract: The origin and evolution of the solar system are analyzed. Physical processes are first discussed, followed by experimental studies of plasma-solid reactions and chemical and mineralogical analyses of meteorites and lunar and terrestrial samples.
236 citations
143 citations
TL;DR: The combination of the Doppler data from the first two Juno science orbits provides an improved estimate of the gravity field of Jupiter, crucial for interior modeling of giant planets as mentioned in this paper.
Abstract: The combination of the Doppler data from the first two Juno science orbits provides an improved estimate of the gravity field of Jupiter, crucial for interior modeling of giant planets The low-degree spherical harmonic coefficients, especially J4 and J6, are determined with accuracies better than previously published by a factor of 5 or more In addition, the independent estimates of the Jovian gravity field, obtained by the orbits separately, agree within uncertainties, pointing to a good stability of the solution The degree 2 sectoral and tesseral coefficients, C2,1, S2,1, C2,2, and S2,2, were determined to be statistically zero as expected for a fluid planet in equilibrium
81 citations
TL;DR: In this article, a theoretical model for the Jovian magnetosphere whose pressure is comparable to the corotational energy density has been presented, which predicts a thin current sheet of 1 Jupiter radius to 2 Jupiter radii half-thickness.
Abstract: A theoretical model is presented for the plasma in the Jovian magnetosphere whose pressure is comparable to the corotational energy density. The model predicts a thin current sheet of 1 Jupiter radius to 2 Jupiter radii half-thickness. The current sheet lies almost precisely in the magnetic equatorial plane and is not appreciably warped as suggested previously.
71 citations
References
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15 May 1971
TL;DR: Mathematical formulation of Double Precision Orbit Determination Program /DPODP/ for lunar and planetary mission spacecraft trajectories is presented in this article, where the authors consider the case of two spacecraft.
Abstract: Mathematical formulation of Double Precision Orbit Determination Program /DPODP/ for lunar and planetary mission spacecraft trajectories
176 citations
TL;DR: The mean scale height of the Jovian upper atmosphere is 32 plus or minus 6 km near -10 deg zenographic latitude, 31 plus or plus 2 km at -47 deg Zný latitude, and 24 plus or negative 2km at -57 deg Zwicker.
Abstract: Use of computer-controlled one-dimensional area-scanning photometers to observe the occultation of the Beta Scorpii system by Jupiter on May 13, 1971. Six high-quality light curves were obtained; three of the occultations of the brighter component Beta Sco A and three of Beta Sco C. The mean scale height of the Jovian upper atmosphere is 32 plus or minus 6 km near -10 deg zenographic latitude, 31 plus or minus 2 km at -47 deg zenographic latitude, and 24 plus or minus 2 km at -57 deg zenographic latitude. The determination of the atmospheric scale height is highly sensitive to the background level subtracted, providing a possible explanation of an earlier result by Baum and Code (1953) placing the scale height at about 8 km. Correlated departures of the light curve from a theoretical isothermal curve are reproduced in the three bright-star curves, and are thus not due to random density fluctuations in the Jovian atmosphere, but are rather due to global stratification. Details of the stratification, which includes at least a number of warm layers, are examined by deconvolution of the light curves. There is evidence for a high-temperature (T greater than 300 K) thermosphere on two of the bright-star light curves.
56 citations
TL;DR: By fitting the two occultation durations as chords to a model disk, the diameter is found to be 5270 (+30, -∼200) kilometers, the major error contribution arising from the uncertain atmospheric thickness below the occultation layer.
Abstract: On 7 June 1972 the third, Jovian satellite Ganymede occulted the eighth-magnitude star SAO 186800. Successful photoelectric observations obtained at Lembang, Java (Indonesia), and Kavalur, India, show nonabrupt immersions and emersions, indicating the presence of an atmosphere whose surface pressure is greater than about 10^(-3) millibar. By fitting the two occultation durations as chords to a model disk, the diameter is found to be 5270 (+30, -∼200) kilometers, the major error contribution arising from the uncertain atmospheric thickness below the occultation layer. The derived mean density is 2.0 (-0.03, + ∼0.2) grams per cubic centimeter.
52 citations
25 citations