Rotation Of Jupiter Research Articles

Zenomagnetic core-mantle coupling and the rotation of Jupiter's Great Red Spot

Fluctuations of the order of several seconds in the period of rotation of Jupiter's Great Red Spot have been observed by Reese and Solberg (1966) to occur within intervals of not more than a few months. On Hide's (1961) hypothesis that the Red Spot is a persistent feature attached to the solid surface of the planet, these fluctuations may indicate an internal redistribution of Jupiter's angular momentum. Evidence for a strong zenomagnetic field and for a transition from the molecular to the metallic phase of hydrogen at pressures of a few Mb have led Gallet (1961) and Runcorn (1967) to suggest that angular momentum may be transferred between the solid molecular hydrogen mantle and a liquid metallic core. Adopting their model for Jupiter's interior and using the theory of electromagnetic coupling which has successfully explained the irregular changes in the Earth's rotation period, the electrical conductivity of the Jovian mantle can be estimated. The result is not inconsistent with such slight evidence as exists for changes in the rotation period of the decametre radio sources.

Jupiter's rotation

Analysis of all available observations of Jovian dekametric emission to the end of 1969, shows that Jupiter's rotation period is constant at 9h 55m 29·70 ± 0·05s.

Physical Sciences: Sunspots And Planetary Orbits

THE possibility of a relationship between the periods of the sunspot cycle and the periods of the rotation of the planets has been investigated by several authors1–5. Such an interaction could be mediated by non-linear processes of gravitational wave conversion of the type which may, for example, be responsible for the acceleration of the equator of the Sun6,7. On the face of things, the most likely relationship should be that between the sunspot cycle and the period of rotation of Jupiter, gravitationally the dominant planet, but non-linear may imply that cross modulation products representing the combined effects of two or more planets may be the most easily recognizable.

Jupiter's Decametric Rotation Period

The mean value of Jupiter's rotation period over an assumed 11.86-year drift cycle was found to be 9h55m29 ~73 ± 0 s04. The position of source A in a central-meridian-longitude system based on the new rotation period displayed a correlation with the Jovicentric declination of the Earth distinctly higher than its anticorrelation with the sunspot number, substantiating an earlier suggestion that the observed drift is a geometrical effect due to Jupiter's changing aspect in its orbit around the Sun. A model consist- ing of a single curved emission sheet fixed to the magnetic field can be made to account for the observed drifts of sources A and B

Jupiter's rotation period

The current belief that Jupiter's rotation period has recently lengthened by 0·8 sec is an error arising from a secular increase of duration of Jovian decametric storms. Periodograms based on the commencement time of decametric storms yield a constant period, 9 h 55 m 29·70 s ± 0·05 s.

Radiophysics of Jupiter

Radiophysics of Jupiter

Magnetosphere of Jupiter

THE rotation of Jupiter is very rapid (36°/h). If its magnetospheric plasma corotates with the planet, the effect of centrifugal force on the plasma distribution will be considerable. At 6 equatorial radii from the centre (which corresponds roughly to the orbit of the satellite Io) the centrifugal force on a corotating body is eighteen times that of gravity; the two forces are equal at 2.3 radii. Thus, we may expect that the corotating plasma trapped in the magnetic field will be thrown out to those parts of the lines of force which are the most remote from the axis of rotation. There is, however, a maximum plasma density which can corotate at a given distance from the axis. The magnetic field must be able to exert enough force on the plasma to provide the required centripetal acceleration. If the plasma density is too great, it will break away, carrying the magnetic field with it. We may estimate the maximum number density of the plasma in the equatorial plane by equating the magnetic and rotational kinetic energy densities B is the magnetic induction at radius r = Lr0, where r0 is the equatorial planetary radius and L will later be used to identify the magnetic field line on which this plasma lies. Nmax is the maximum electron or ion number density which can corotate, m the mass of an ion, Ω the angular velocity and μ0 the permeability of free space. Assuming the magnetic field to be that of a dipole aligned along the rotational axis, of induction B0 at the equatorial planetary surface, we find This equation has been derived by a different method by Hines1.

Apparent changes in the rotation rate of Jupiter

The apparent change of Jupiter's rotation rate derived from decameter emission probability histograms is shown to differ from the change derived by comparing dynamic spectra of the radiation. The dynamic spectra indicate that the two major “sources” of radiation shifted longitudes in opposite directions over the period from 1960 through 1965. The drift of histogram features and the drift of spectral features is attributed partly to emission beam divergence as the Earth's declination changes, and partly to a slightly incorrect System III period. The observations are explained by a model in which much of Jupiter's emission (especially the Io-related emission) is beamed in a thin conical sheet from Jupiter's northern hemisphere. On Earth, we observe the two regions where the sheet crosses the ecliptic plane.

Observations of Jupiter at a Frequency of 610.5 MHz.

view Abstract Citations (1) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Observations of Jupiter at a Frequency of 610.5 MHz. Dickel, John R. Abstract A total of 37 measurements of Jupiter have been made at a frequency of 610.5 MHz with the 400-ft radio telescope at the Vermilion River Observatory of the University of Illinois. The results give a mean flux density for the planet of 5.2 ~ 1.0 flux units [1 0~26 W m-2 (Hz)-1i for a normalized distance to Jupiter of 4.04 a.u. The telescope receives left-hand circular polarization so that the radiation recorded will not include possible right-hand circularly polarized components which may be generated in the Jovian magnetosphere. The radiation appears to vary by almost 25 % with the rotation of Jupiter. The intensity reaches its minimum value when the magnetic pole in the noril~ern hemisphere, at about x111=2000, lies on the central meridian. This variation is consistent with the beaming of the radiation into il~e plane of Jupiter's magnetic equator. The results can be combined with other measurements in order to determine the spectrum of the radiation and the physical properties of the Jovian magnetosphere. This research was sponsored by the Office of Naval Research under contract XONR 1834(22). Publication: The Astronomical Journal Pub Date: February 1966 DOI: 10.1086/110069 Bibcode: 1966AJ.....71R.159D full text sources ADS |

The Stratospheric Rotation of Jupiter in November 1963

The Stratospheric Rotation of Jupiter in November 1963

Radio observations of the planet Jupiter

Radio observations of Jupiter made in June 1954 and November 1, 1955, to March 13, 1956, are reported. Three aspects of the program are discussed: (1) Correlation of observation with the rotation of Jupiter; (2) Polarization of the radiation; (3) Frequency characteristics. During the period of observation, there were at least three centers of activity on the planet, rotating approximately with the non-equatorial regions. No definite correlation of radio noise with visible features was noted. The white spot DE, noted as a possible correlation in 1951 data, was definitely not well correlated with radio noise occurrences in 1955–56. The most active radio region exhibited a rotational period of 9h55m33s, a value consistent with other determinations and also consistent with the suggested long-term rotational period, system III. Most of the radio noise bursts were strongly circularly polarized. For the most active region, only bursts of right circular polarization were observed. The radio noise spectrum does not appear to be continuous over the observed set of frequencies. The hypothesis that the narrow angle of visibility is evidence for critical reflection by the ionosphere of Jupiter is not supported by the combined Carnegie and Australian observations.

18?3 Mc/s Radiation from Jupiter

Burke and Franklin's discovery of radio emission from Jupiter has been confirmed. Examination of old records has shown that in 1950?51 the radiation came in groups of bursts of very high intensity. Bursts have durations of the order of a minute or less; groups, of an hour. Because of the remarkably close relation between active periods and the period of rotation of Jupiter, it is inferred that the source at the time was very localized. Its identification with a visual disturbance in the South Temperate Belt is very probable.

THE PERIOD OF ROTATION OF JUPITER'S THIRD SATELLITE

THE PERIOD OF ROTATION OF JUPITER'S THIRD SATELLITE

Our Astronomical Column

ROTATION OF JUPITER.—Most of the determinations of the rotation period of Jupiter have been made by observations of surface markings between latitudes 45° N. and 35° S., and little has been known as to the conditions of rotation near the poles. This is due to the fact that conspicuous and sufficiently definite spots are chiefly confined to the equatorial regions of the planet, and partly to the unfavourable conditions under which the poles are presented to us. Some important observations, however, bearing on the rotation in high latitudes, have been secured by Mr. Stanley Williams with the aid of a 6½-inch Calver reflector (Asi. Nach., 3325). On October 10, 1892, a short dusky streak, almost oblong in appearance, was observed quite close to the north limb of Jupiter, and reaching at least as far as 85° N. Other streaks of similar appearance were subsequently observed, and frequent observations of the times of mid-transit were made. Confirmation of the results has been obtained by an examination of several photographs of the planet taken at the Lick Observatory about the same period, the markings being sufficiently distinct for measurement. Generally speaking, the visual agree very closely with the photographic results, the mean rotation period derived by the two processes only differing by about two seconds. The mean result for the rotation period of the surface material of Jupiter, between north latitudes 40° and 85°, is 9h. 55m. 38˙9s. ± 1˙20s., this being the length of a sidereal rotation expressed in mean solar time. The following statement illustrates the degree of accuracy obtained:—

Our Astronomical Column

THE DEARBORN OBSERVATORY, CHICAGO.—The annual report from Prof. Hough to the Board of Directors of the Chicago Astronomical Society, dated May last, has been issued. The planet Jupiter has been made a special object of study with the great equatorial, the first observation having been secured on May 6, 1880, and the last on January 30, 1881. The observations made at the Dearborn Observatory do not support the idea that the surface of the planet is “subject to sudden and rapid changes, which may be accomplished in a few days or even a few hours.” On the contrary, the observations in question show that all minor changes in the markings or spots have been slow and gradual. “In fact the principal features have been permanent, no material change being detected by micrometer measurement.” With regard to the rotation of Jupiter, the discussion of the measures on the great red spot made from September 25, 1879, to January 27, 1881, or over a period of 490 days, gave for the mean value 9h. 55m. 35·2s., but when the individual observations are compared with it, a well-marked maximum displacement of the centre of the spot, to the amount of 1°·4, is exhibited, apparently indicating that it gradually oscillated to this extent in longitude, which on the surface of Jupiter corresponds to about 3200 miles. The observations however may be well represented by making the period of rotation a function of the time; thus the period 9h. 55m. 33·2s. + 0·18s. √t is found to satisfy all the measures with a mean maximum error of 0″·5: the zero-epoch being September 25, 1879, and t the number of days after that date. The mean-rotation period derived from observations of polar spots is 9h. 55m. 35·1s., that deduced from the small spots indicating an average displacement during two months of 2″, or about 4600 miles. The rotation resulting from the observations of equatorial spots is 9h. 50m. 9·8s. with uniform motion. Prof. Hough states that the actual size of the great red spot, as seen with the Chicago telescope (18½ inches aperture) is—length, 29,600 miles; breadth, 8300 miles; and he remarks that smaller telescopes make the approximate length considerably less than the real value.

Scientific Serials

Bulletin de l'Académie Imperiale des Sciences de St. Petersburg, t. xxvii., No. 1, February, 1881.—On the results of experiments on the resistance of the air and their application to the solution of problems of firing, by M. Mayevsld.—On variations of the fur and on the geographical distribution of the sea-otter (Enhydris marina), by M. Brandt.—On the integration of partial equations of the first order with several variables whose co-efficients are constant, by M. Alexéeff.—On the rotation of Jupiter, by M. Kortazzi.—Crystals of beryl from a part of the Southern Oural, by M. Kokscharow.—On the formation of some nitrated derivatives of some hydrocarbons of the fatty series by direct action of nitric acid, by M. Konowalof.—On the variability of forms of Lubomirskia Baïcalensis, and on the distribution of sponges of Lake Baikal, by M. Dybowski.—On universal time, and on the choice for this purpose of a prime meridian, by M. Struve.—Anatomy of the lactiferous glands during the period of lactation, by M. Saeffligen.—On the speclroscopy of hydrogen, by M. Hasselberg.

Spectroscopic Results for the Rotation of Jupiter and of the Sun, obtained at the Royal Observatory, Greenwich

Spectroscopic Results for the Rotation of Jupiter and of the Sun, obtained at the Royal Observatory, Greenwich

On the time of rotation of Jupiter

On the time of rotation of Jupiter

V. On the time of rotation of Jupiter

V. On the time of rotation of Jupiter