Abstract
During the Pioneer Saturn encounter, a continuous round-trip radio link at S band (∼2.2 gigahertz) was maintained between stations of the Deep Space Network and the spacecraft. From an analysis of the Doppler shift in the radio carrier frequency, it was possible to determine a number of gravitational effects on the trajectory. Gravitational moments (J2 and J 4) for Saturn have been determined from preliminary analysis, and preliminary mass values have been determined for the Saturn satellites Rhea, Iapetus, and Titan. For all three satellites the densities are low, consistent with the compositions of ices. The rings have not been detected in the Doppler data, and hence the best preliminary estimate of their total mass is zero with a standard error of 3×10-6 Saturn mass. New theoretical calculations for the Saturn interior are described which use the latest observational data, including Pioneer Saturn, and state-of-the-art physics for the internal composition. Probably liquid H2O and possibly NH 3 and CH4 are primarily confined in Saturn to the vicinity of a core of approximately 15 to 20 Earth masses. There is a slight indication that helium may likewise be fractionated to the central regions.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 449-453 |
| Number of pages | 5 |
| Journal | Science |
| Volume | 207 |
| Issue number | 4429 |
| State | Published - 1980 |
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Pioneer Saturn celestial mechanics experiment. / Anderson, John D.; Null, George W.; Biller, Elinor D.; Wong, Sun Kuen; Hubbard, William B.; MacFarlane, Joseph J.
In: Science, Vol. 207, No. 4429, 1980, p. 449-453.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Pioneer Saturn celestial mechanics experiment
AU - Anderson, John D.
AU - Null, George W.
AU - Biller, Elinor D.
AU - Wong, Sun Kuen
AU - Hubbard, William B.
AU - MacFarlane, Joseph J.
PY - 1980
Y1 - 1980
N2 - During the Pioneer Saturn encounter, a continuous round-trip radio link at S band (∼2.2 gigahertz) was maintained between stations of the Deep Space Network and the spacecraft. From an analysis of the Doppler shift in the radio carrier frequency, it was possible to determine a number of gravitational effects on the trajectory. Gravitational moments (J2 and J 4) for Saturn have been determined from preliminary analysis, and preliminary mass values have been determined for the Saturn satellites Rhea, Iapetus, and Titan. For all three satellites the densities are low, consistent with the compositions of ices. The rings have not been detected in the Doppler data, and hence the best preliminary estimate of their total mass is zero with a standard error of 3×10-6 Saturn mass. New theoretical calculations for the Saturn interior are described which use the latest observational data, including Pioneer Saturn, and state-of-the-art physics for the internal composition. Probably liquid H2O and possibly NH 3 and CH4 are primarily confined in Saturn to the vicinity of a core of approximately 15 to 20 Earth masses. There is a slight indication that helium may likewise be fractionated to the central regions.
AB - During the Pioneer Saturn encounter, a continuous round-trip radio link at S band (∼2.2 gigahertz) was maintained between stations of the Deep Space Network and the spacecraft. From an analysis of the Doppler shift in the radio carrier frequency, it was possible to determine a number of gravitational effects on the trajectory. Gravitational moments (J2 and J 4) for Saturn have been determined from preliminary analysis, and preliminary mass values have been determined for the Saturn satellites Rhea, Iapetus, and Titan. For all three satellites the densities are low, consistent with the compositions of ices. The rings have not been detected in the Doppler data, and hence the best preliminary estimate of their total mass is zero with a standard error of 3×10-6 Saturn mass. New theoretical calculations for the Saturn interior are described which use the latest observational data, including Pioneer Saturn, and state-of-the-art physics for the internal composition. Probably liquid H2O and possibly NH 3 and CH4 are primarily confined in Saturn to the vicinity of a core of approximately 15 to 20 Earth masses. There is a slight indication that helium may likewise be fractionated to the central regions.
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M3 - Article
AN - SCOPUS:37049185039
VL - 207
SP - 449
EP - 453
JO - Science
JF - Science
SN - 0036-8075
IS - 4429
ER -