Positions Of Jupiter Research Articles

Astrometric Results for Observations of Jupiter’s Galilean Satellites During Mutual Occultations and Eclipses in 2009 and 2014–2015

Photometric observations of satellites during their mutual occultations and eclipses are a valuable source of astrometric data for studying the motion of natural planetary satellites. Worldwide photometric observation campaigns are organized in order to observe as many phenomena as possible. All the photometric results obtained during such an observation campaign are stored in a single database, and after some time, they undergo astrometric processing. After conducting the campaign and publishing the results, some observers find unused data, which appear valuable. We have collected these photometric observations of mutual occultations and eclipses of Jupiter’s Galilean satellites and processed them to utilize these valuable astrometric data. To obtain astrometric data from the photometric observations, we have applied our original method. The observations come from eight observatories worldwide. As a result, this work presents 32 new relative astrometric positions of Jupiter’s Galilean satellites in 2009 and 23 new positions in 2014–2015. The astrometric accuracy of the new data in comparison with the most developed theory (O–C) is approximately 0.05′′. The internal accuracy, based on estimates for random photometry errors, is 0.02′′.

Precise CCD positions of Himalia using Gaia DR1 in 2015-2016

In order to obtain high precision CCD positions of Himalia, the sixth Jovian satellite, a total of 598 CCD observations have been obtained during the years 2015-2016. The observations were made by using the 2.4 m and 1 m telescopes administered by Yunnan Observatories over 27 nights. Several factors which would influence the positional precision of Himalia were analyzed, including the reference star catalogue used, the geometric distortion and the phase effect. By taking advantage of its unprecedented positional precision, the recently released catalogue Gaia DR1 was chosen to match reference stars in the CCD frames of both Himalia and open clusters which were observed for deriving the geometric distortion. The latest version of SOFA library was used to calculate the positions of reference stars. The theoretical positions of Himalia were retrieved from the Jet Propulsion Laboratory Horizons System which includes the satellite ephemeris JUP300, while the positions of Jupiter were based on the planetary ephemeris DE431. Our results showed that the means of observed minus computed (O-C) residuals are 0.071 and -0.001 arcsec in right ascension and declination, respectively. Their standard deviations are estimated at about 0.03 arcsec in each direction.

Preliminary results of CCD observations targeting Himalia acquired at Yunnan Observatories in 2015

In order to study the potential associated with high precision CCD astrometry of irregular satellites, we have acquired experimental observations of Himalia, the sixth and irregular satellite of Jupiter. A total of 185 CCD observations were obtained by using the 2.4m and 1m telescopes administered by Yunnan Observatories over ten nights. Preliminary analysis of the observations were made, including geometric distortion, atmospheric refraction, and also the phase effect. All positions of Himalia are measured relative to the reference stars from the catalog UCAC4 in each CCD field of view. The theoretical positions of Himalia were retrieved from the Institute de Méchanique Céleste et de Calcul des Éphémérides, while the positions of Jupiter were obtained based on the planetary ephemeris INPOP13c. The results show that the means of observed minus computed (O – C) residuals are −0.004″ and −0.002″ in right ascension and declination, respectively. The standard deviations of (O – C) residuals are estimated to be about 0.04″ in each direction.

Observations of the Galilean moons of Jupiter in 2013–2015 at Pulkovo

Observational results are presented for Jupiter and its Galilean moons from the Normal Astrograph at Pulkovo Observatory in 2013–2015. The following data are obtained: 154 positions of the Galilean satellites and 47 calculated positions of Jupiter in the system of the UCAC4 (ICRS, J2000.0) catalogue; the differential coordinates of the satellites relative to one another are determined. The mean errors of the satellites’ normal places in right ascension and declination over the entire observational period are, respectively: eα = 0.0065″ and eδ = 0.0068″, and their standard deviations are σα = 0.0804″ and σδ = 0.0845″. The equatorial coordinates are compared with planetary and satellite motion theories. The average (O–C) residuals in the two coordinates relative to the motion theories are 0.05″ or less. The best agreement with the observations is achieved by a combination of the EPM2011m and V. Lainey-V.2.0|V1.1 motion theories; the average (O–C) residuals are 0.03″ or less. The (O–C) residuals for the features of the positions of Io and Ganymede are comparable with measurement errors. Jupiter’s positions calculated from the observations of the satellites and their theoretical jovicentric coordinates are in good agreement with the motion theories. The (О–С) residuals for Jupiter’s coordinates are, on average, 0.027″ and–0.025″ in the two coordinates.

Observations of the Galilean satellites of Jupiter with Pulkovo Normal Astrograph during 2009–2011

The paper presents the results of observations of Jupiter and its Galilean moons, performed with the Normal Astrograph (D/F=0.33 m/3.5 m, CCD S2C, FOV 18′ × 16′) at Pulkovo observatory during 2009–2011. We obtained 140 positions of the Galilean satellites and 42 calculated positions of Jupiter in the system of UCAC4 (ICRS, J2000.0) catalogue. The equatorial coordinates of satellites have been compared to eight most current theories of planetary and satellite motion. The average residuals between the observed and calculated coordinates (O–C) using the selected theories of motion do not exceed 0.08″. The behavior and magnitudes of the (O–C) residuals in the positions of Ganymede and Callisto satellites show that the theory of their motion was elaborated worse than in the case of Io and Europa satellites. Distribution of the (O-C) residuals for Callisto differs from a normal distribution. Comparison of the calculated equatorial coordinates of Jupiter, based on the observed positions of satellites and their theoretical Jovi-centric coordinates calculated using the INPOP10 theory of planetary motion revealed satisfactory results. The average residuals are, respectively, (O–C)α = 0.040″ and (O–C)δ =–0.053″ assuming the normal distribution law.

Jovian satellite positions from Hubble Space Telescope images

An accurate technique has been developed for measuring planetocentric positions of Jupiter's satellites from Wide Field/Planetary Camera images. Our method of finding the centers of the satellites and planet is based upon established limb-fitting techniques, but we have adapted those techniques to astrometry. We compare our limb-fitting results with previously published work and discuss its errors. A model ellipse is generated from the physical ephemeris of the planet including its phase defect. Then the planet center coordinates are computed by fitting the model to the limb observations using the method of least squares. A satellite position is determined similarly, and its offset from the planet is calculated. A total of 76 positions of the galileans satellites, the small moon Amalthea, and the shadows of Io and Ganymede cast on Jupiter have been measured on 61 images. Comparison between the observational results and JPL satellite ephemerides demonstrates the validity of this new method of analysis. The accuracy of the galilean satellite measurements is estimated to be 0.04 arcsec in right ascension and in declination.

Jovian electron modulations by the solar wind interaction with the magnetosphere

Variations of energetic electrons released from the Jovian magnetosphere are investigated in detail by using data from three spacecraft, Pioneer 10, 11, and Ulysses. Analyses with the three spacecraft data confirmed that the Jovian electrons are modulated by the dynamic pressure of the solar wind at the position of Jupiter. It is also found that the release rate of energetic electrons is controlled by the polarity of IMF having dawn-dusk or latitudinal dependence. The enhancements of released electron flux were detected during the toward polarity of IMF when the spacecraft were located in the upstream or dawn side of Jupiter. On the other hand, Ulysses detected enhancement in away polarity of IMF when the spacecraft was on the duskside of southern hemisphere. We made a simulation to reproduce the electron variation of Jovian electrons observed by Pioneer 11 considering the convective and diffusive transport in the interplanetary medium. According to the simulation, the observed enhancements of electron flux originating from Jupiter are well represented by the coupling of both the source modulation at the Jovian magnetosphere and the transport effect in the interplanetary medium.

Determination of Position of Jupiter From Very-Long Baseline Interferometry Observations of ULYSSES

Very-long baseline interferometry (VLBI) observations of the Ulysses spacecraft near its encounter with Jupiter on 1992 February 8 were made to determine the angular position of Jupiter with respect to well known extragalactic radio sources. Spacecraft range and Doppler data were used to determine the position of the spacecraft with respect to Jupiter. Thirty-one VLBI observations of the spacecraft were made within 30 days of Ulysses closest approach to Jupiter, using the California-Spain and California-Australia baselines of NASA's Deep Space Network. When combined, these data determine the position of Jupiter at the time of encounter with an accuracy of 0.003 min in right ascension and 0.005 sec in declination. In addition, the Earth-Jupiter distance was determined with 20 m accuracy.

First direct measurement of the beaming of Jupiter's decametric radiation

ONE of the most important features of the jovian decametric radioemission comes from the geometry of the observed radiation. The emission occurrence probability appears as a well defined function of the respective positions of Jupiter, the observer and the innermost galilean satellite Io, exhibiting several major sources which correspond to narrow ranges in zenocentric observer's longitude L (the so-called central meridian longitude) and in the synodic orbital phase of Io, Φ. These statistically established directivity properties were defined by Warwick1 and Alexander2, who showed that the repetition of the distinguishable dynamic spectra associated with each source occurring in a longitude range of 20°, is attributable to a ±10° beaming cone into which the radiation escapes in the ecliptic plane. Dulk3 stated more precisely that the emission is received on the Earth when Io makes certain angles with the line of sight, and that the dynamic spectrum varies in shape and frequency range with the magnetic longitude of Io. The beaming in latitude is also important4: the ±3.3° variation of the zenocentric declination of the Earth is sufficient to lead to a 15° variation of the statistical apparent sub-Io longitude of the emission. But these conclusions, based on statistics and on the repeatability of similar dynamic spectra in equivalent geometrical configurations of Jupiter, Io and the observer, are not decisive, as they were obtained from a single direction at a given time. We present here the first direct experimental proof of a narrow beaming of Jupiter radiation, using simultaneous observations in two different directions, during the French–Soviet space radio astronomy experiment Stereo-5.

Test for planetary influences on solar activity

A method due to Schuster is used to test the hypothesis that solar activity is influenced by tides raised in the Sun's atmosphere by planets. We calculate the distribution in longtitude of over 1000 flares occurring in a 61/2 yr segment of solar cycle 19, referring the longitude system in turn to the orbital positions of Jupiter and Venus. The resulting distributions show no evidence for a tidal effect.

Venus, Mars and Jupiter Shine

If you think that the evening skies are now more brilliant than usual at this time of year, you are quite right. Added to the display of bright stars visible on late winter evenings are three prominent planets. Two of them-Venus and Jupiter-are brighter than any of the stars. The third, Mars, is exceeded only by Sirius, the dog star. The first to appear is Venus. On March 1 it remains above the western horizon for more than two hours after sunset and at the month's end this is extended to nearly three hours. It is so prominent that you can see it in the west while the evening twilight is still quite bright. Jupiter is high in the south, in the constellation of Gemini, the twins. Although less than a third as bright as Venus, it is so brilliant that you will have no trouble locating it. At the first of the month Mars rises in the east about four hours after sunset and about two hours after on the 31st. Brighter than any star in that part of the sky and distinctly red, it is easy to identify. It is about a tenth as bright as Jupiter. The accompanying maps show the appearance of the skies about 10:00 p.m., your own kind of standard time, at the first of March; 9:00 p.m. on the 15th; and 8:00 p.m. on the 31st. The position of Jupiter is about the same all month; that of Venus (in Aries, the ram) is its location at month's end. During March, Venus moves from the next-door constellation of Pisces, the fishes (not shown on the maps) in Aries. This is a distance in the sky more than from Sirius, in the south to Regulus, high in the southeast. Mars is in Virgo, part of which is shown low in the east, but this planet does not come up until after the times shown on the maps. Sirius, in the south in Canis Major, the great dog, is the brightest star of the night sky. To its right, and a little higher, stands Orion, the warrior, with two more stars rated as first magnitude. These are Betelgeuse, above, and Riegel, below. Between them are the three stars that form Orion's belt. Farther right stands Taurus, the bull, with ruddy Aldebaran to mark his eye. Above the great dog is a faint constellation called Monoceros, which means unicorn, and above that is the lesser dog, Canis Minor, with the star Procyon. Still higher is Jupiter and the constellation of Gemini. Pollux is another star rated as first magnitude, but nearby Jupiter outshines it. To the right of Taurus shown on the northern sky map, is Auriga, the charioteer, with bright Capella. Three more bright stars, also rated by astronomers as first magnitude, are in the eastern evening sky. One is Regulus, high in the southeast in Leo, the lion. In the northeast is Bootes, the herdsman, with bright Arcturus. The third is Spica, near the eastern horizon, in Virgo, the virgin, but this star is so low that atmospheric absorption dims its light considerably; thus it is shown as magnitude three.

The position of Jupiter's Van Allen belt

This paper reports a series of measurements of the location of the centroid of the 11.3-cm Jovian radio emission relative to a nearby radio source whose position is known from a lunar occultation. The mean position of the centroid of the Jovian emission is close to the center of the planet, and any periodic movement as the planet rotates is much less than reported by Berge and Morris.

Radiation from Jupiter at 178 Mc/s

Observations were made of the decimeter radio emission from Jupiter at a frequency of 178 Mc over the period June 22 to July 1, 1983, using both a fan- beam system and an interferometer. A procedure was developed in which the records obtained on one day are subtracted from those taken on another day when the position of Jupiter has altered by more than the beam width of the instrument. The mean values derived for flux density were 3.3 plus or minus 0.45 x 10/sup - 26/ w m/sup -2/(cps)/sup -1/ for the fan beam and 3.8 plus or minus 0.4 x 10/ sup -26/ w m/sup -2/(cps)/sup -1/ for the interferometer. It was concluded that, over the period of observation, the flux density of Jupiter did not vary by more than 20%. (M.C.G.)

Observations at 610 Megacycles/Sec of the Radiation from Jupiter

BS>Data obtained during April 1962 are presented from measurements of non-thermal radiation from Jupiter. Observations of discrete radio sources at 610 mc (49 cm wave-length) were made using the Royal Radar Establishment interferometer. Each observation was made with the arials following the position of Jupiter to give an interference record lasting about three-quarters of an hour. Observations were made at various hour angles and, for observations away from transit, path lengths were equalized by means of additional cable to make sure that the chromatic coherence curve went through a maximum. A 20-min extract from a typical interference record is presented and discussed. (C.H.)

Positions of Jupiter's satellites VI-XI, Saturn's satellite IX (Phoebe), and Pluto

Positions of Jupiter's satellites VI-XI, Saturn's satellite IX (Phoebe), and Pluto

Positions of Jupiter's satellites

Positions of Jupiter's satellites

Positions of jupiter's satellites and asteroids

Positions of jupiter's satellites and asteroids

Positions of Jupiter's eighth satellite

Positions of Jupiter's eighth satellite

Positions of Jupiter VIII and asteroids

Positions of Jupiter VIII and asteroids

Occultations of Stars by the Moon, observed at the Astronomical Observatory, Kiew, in the year 1927; and Micrometer Observations of the Position of Jupiter

Occultations of Stars by the Moon, observed at the Astronomical Observatory, Kiew, in the year 1927; and Micrometer Observations of the Position of Jupiter