This data set contains the data from the Ulysses dust detector system (UDDS) from start of mission through the end of mission, 1990-2007. (As the dust detector was turned off after Nov. 30, 2007, this is the last date for which UDDS data is recorded.) Included are the dust impact data, noise data, laboratory calibration data, and location and orientation of the spacecraft and instrument.
The dust detector system on board the Galileo spacecraft recorded dust impacts in circumjovian space during the craft's orbital mission about Jupiter. This is the eighth in a series of papers dedicated to presenting Galileo and Ulysses dust data. We present data from the Galileo dust instrument for the period January 1997-December 1999 when the spacecraft completed 21 revolutions about Jupiter. In this time interval data were obtained as high resolution realtime science data or recorded data during 449 days (representing 41% of the entire period), or via memory readouts during the remaining times. Because the data transmission rate of the spacecraft was very low, the complete data set (i.e. all parameters measured by the instrument during impact of a dust particle) of only 3% (7625) of all particles detected could be transmitted to Earth; the other particles were only counted. Together with the data of 2883 particles detected during, Galileo's interplanetary cruise and 53 53 particles detected in the jovian system in 1996, complete data of 15 861 particles detected by the Galileo dust instrument from 1989 to 1999 are now available. The majority of the detected particles were tiny grains (about 10 nm in radius), most of them originating from Jupiter's innermost Galilean moon Io. They were detected throughout the jovian system and the highest impact rates exceeded 100 min(-1) (C21 orbit; 01 July 1999). With the new data set the times of onset, cessation and a 180 degrees shift in the impact direction of the grains measured during 19 Galileo orbits about Jupiter are well reproduced by simulated 9 nm particles charged up to a potential of +3 V, confirming earlier results obtained for only two Galileo orbits (Horanyi, M., Grun, E., Heck, A., 1997. Modeling the Galileo dust measurements at Jupiter. Geophys. Res. Lett. 24, 2175-2178). Galileo has detected a large number of bigger particles mostly in the region between the Galilean moons. The average radius of 370 of these grains measured in the 1996-1999 period is about 2 mu m (assuming spherical grains with density 1 g cm(-3)) and the size distribution rises steeply towards smaller grains. The biggest detected particles have a radius of about 10 mu m. (c) 2006 Elsevier Ltd. All rights reserved.
The Ulysses spacecraft has been orbiting the Sun on a highly inclined ellipse (i=79∘, perihelion distance 1.3AU, aphelion distance 5.4AU) since it encountered Jupiter in 1992. Between January 2000 and December 2004, the spacecraft completed almost an entire revolution about the Sun, passing through perihelion in May 2001 and aphelion in July 2004. In this five-year period the dust detector on board recorded 4415 dust impacts. We publish and analyse the complete data set of both raw and reduced data for particles with masses 10-16g⩽m⩽10-7g. Together with 1695 dust impacts recorded between launch of Ulysses and the end of 1999 published earlier (Grün, E., Baguhl, M., Divine, N., Fechtig, H., Hamilton, D.P, Hanner, M.S., Kissel, J., Lindblad, B.A., Linkert, D., Linkert, G., Mann, I., McDonnell, J.A.M., Morfill, G.E., Polanskey, C., Riemann, R., Schwehm, G.H., Siddique, N., Staubach, P., Zook, H.A., 1995a. Two years of Ulysses dust data. Planetary Space Sci. 43, 971–999, Paper III; Krüger, H., Grün, E., Landgraf, M., Baguhl, M., Dermott, S.F., Fechtig, H., Gustafson, B.A., Hamilton, D.P., Hanner, M.S., Horányi, M., Kissel, J., Lindblad, B., Linkert, D., Linkert, G., Mann, I., McDonnell, J.A.M., Morfill, G.E., Polanskey, C., Schwehm, G.H., Srama, R., Zook, H.A., 1995. Three years of Ulysses dust data: 1993 to 1995. Planetary and Space Sci. 47, 363–383, Paper V; Krüger, H., Grün, E., Landgraf, M., Dermott, S.F., Fechtig, H., Gustafson, B.A., Hamilton, D.P., Hanner, M.S., Horányi, M., Kissel, J., Lindblad, B., Linkert, D., Linkert, G., Mann, I., McDonnell, J.A.M., Morfill, G.E., Polanskey, C., Schwehm, G.H., Srama, R., Zook, H.A., 2001b. Four years of Ulysses dust data: 1996 to 1999. Planetary Space Sci. 49, 1303–1324, Paper VII), a data set of 6110 dust impacts detected with the Ulysses sensor between October 1990 and December 2004 is now available. The impact rate measured between 2000 and 2002 was relatively constant with about 0.3 impacts per day showing a maximum at 1.5 per day around ecliptic plane crossing in early-2001. The impact direction of the majority of impacts between 2000 and 2002 is compatible with particles of interstellar origin, the rest are most likely interplanetary particles. In 2003 and 2004 dust stream particles originating from the jovian system dominated the overall impact rate. Twenty-two individual dust streams were measured between November 2002 and December 2004. The observed impact rates are compared with models for interplanetary and interstellar dust. The dust measurements from the entire mission since Ulysses launch give good agreement with the interplanetary flux model of Staubach, P., Grün, E., Jehn, R., 1997. The meteoroid environment near Earth, Adv. Space Res. 19, 301–308.
Meteor radar observations carried out in August-September 1953-84 at the Onsala Space Observatory in Sweden show long-term, as well as short term variations in meteor radar rates. These rate variations are associated with position in the solar cycle, and with variations in the solar wind sector structure. An inverse correlation is found between meteor radar rates and the solar cycle. The magnitude of this effect is quite large; about twice as many radar echoes are observed at solar minimum as at solar maximum. We propose that this long-term inverse correlation with the sunspot number is caused by a solar cycle controlled variation of the atmospheric density gradient at meteor ablation heights (90-110 km).Day-to-day variations in meteor radar rates, which correlate with short-term geomagnetic activity have also been detected. A superposed epoch analysis based on solar wind sector boundaries as key dates shows that a minimum in meteor radar rates occurs about 3 days after the Earth's passage of a solar wind sector boundary.
The IAU Meteor Data Center in Lund has acted as a central depository for meteor orbits obtained by photographic, video and radar techniques. The database of precisely reduced photographic meteors contains data on 4581 meteor orbits obtained by 17 different stations or groups in the period 1936–1996. The orbital and geophysical data are available in two separate files as well as in an alternative file with the merged data. In various studies of meteoroid streams as well as in studies of the sporadic meteor background, it is often necessary to utilize both the orbital and the geophysical data files. Since the database is a compilation of partial, not perfectly compatible catalogues from many observing stations, the merging of parameters from one data set to another may sometimes present problems. The present contribution is a note on some problems encountered in the merging procedure. Moreover, it is evident that the database includes a small amount of erroneous data – either in the observations or in the subsequent data reductions. The latter error is not surprising in view of the lack of modern computers at several stations in the past. A final, corrected version of the IAU MDC Lund photographic meteor orbits (eq. 2000.0) can now be requested through the homepage of the Astronomical Institute, Slovak Academy of Sciences (http://www.astro.sk/~ne/IAUMDC/Ph2003/database.html).
The purpose of the IAU Meteor Data Center is to archive, document anddisseminate information on meteoroid orbits. At present 4581 preciselyreduced photographic recordings, 1425 video recordings and 63330 radardetermined orbits are archived at the center.
The database of photographic meteor orbits of the IAU Meteor Data Center in Lund has gradually been updated. The version 2001, which has been prepared for distribution and which will be released soon, contains complete orbital and geophysical data on 4581 meteors (equinox J2000.0).A new meteor identification code consisting of the publication serial number, the author or station code and number of the catalogue is introduced. The verification of mutually dependent parameters has been performed.All the files with the pertinent documentation will be placed on a www-site to enable their free, public downloading.
The Ulysses spacecraft is orbiting the Sun on a highly inclined ellipse (i=79°, perihelion distance 1.3 AU, aphelion distance 5.4 AU). Between January 1996 and December 1999 the spacecraft was beyond 3 AU from the Sun and crossed the ecliptic plane at aphelion in May 1998. In this 4-yr period 218 dust impacts were recorded with the dust detector on board. We publish and analyse the complete data set of both raw and reduced data for particles with masses 10−16–10−8g. Together with 1477 dust impacts recorded between launch of Ulysses and the end of 1995 published earlier (Grün et al., Planet. Space Sci. 43 (1995a) 971; Krüger et al., Planet. Space Sci. 47 (1999b) 363), a data set of 1695 dust impacts detected with the Ulysses sensor between October 1990 and December 1999 is now available. The impact rate measured between 1996 and 1999 was relatively constant with about 0.2 impacts per day. The impact direction of the majority of the impacts is compatible with particles of interstellar origin, the rest are most likely interplanetary particles. The observed impact rate is compared with a model for the flux of interstellar dust particles. The flux of particles several micrometres in size is compared with the measurements of the dust instruments on board Pioneer 10 and Pioneer 11 beyond 3 AU (Humes, J. Geophys. Res. 85 (1980) 5841). Between 3 and 5 AU, Pioneer results predict that Ulysses should have seen 5 times more (∼10μm sized) particles than actually detected.
The dust detector system onboard Galileo has recoding dust impacts in circumjovian space since the spacecraft was injected into a bound orbit about Jupiter in December 1995. This is the sixth in a series of papers dedicated to presenting Galileo and Ulysses dust data. We present data from the Galileo dust instrument for the period January to December 1996 when the spacecraft completed four orbits about Jupiter (G1, G2, C3 and E4). Data were obtained as high-resolution realtime science data or recorded data during a time period of 100 days, or via memory read-outs during the remaining times. Because the data transmission rate of the spacecraft is very low, the complete data set (i.e. all parameters measured by the instrument during impact of a dust particle) for only 2% (5353) of all particles detected could be transmitted to Earth; the other particles were only counted. Together with the data for 2883 particles detected during Galileo's interplanetary cruise and published earlier, complete data of 8236 particles detected by the Galileo dust instrument from 1989 to 1996 are now available. The majority of particles detected are tiny grains (about 10nm in radius) originating from Jupiter's innermost Galilean moon Io. These grains have been detected throughout the Jovian system and the highest impact rates exceeded 100min−1. A small number of grains has been detected in the close vicinity of the Galilean moons Europa, Ganymede and Callisto which belong to impact-generated dust clouds formed by (mostly submicrometer sized) ejecta from the surfaces of the moons (Krüger et al., 1999e. Nature 399, 558). Impacts of submicrometer to micrometer sized grains have been detected throughout the Jovian system and especially in the region between the Galilean moons.
Perseid and sporadic meteor hourly rates and magnitudes observed in 1953–1983 by a team of visual observers at the Onsala Space Observatory, Sweden, are analysed. A high-resolution study of the zenithal hourly rates of bright Perseid meteors (m⩽2.5) versus solar longitude has been made using a step length of 0.05° in solar longitude. The present study, which is based on 147 Perseid hourly rates, observed between solar longitudes 138.70°–141.65° (equinox 2000) covers the period of maximum Perseid activity. Somewhat surprisingly it reveals a multi-peak structure of the Perseid maximum with at least four separate peaks in the activity curve of bright Perseids. The first peak located at 139.38° corresponds to the crossing of the nodal plane of the parent comet, the second at 139.68° is the so-called “new” Perseid maximum, the third peak at 140.20° is the “old” or “traditional” maximum of the shower, while the fourth peak although less intense than the previous three peaks indicates a well-defined activity maximum centred on 140.78°. It is interesting to note that, for bright Perseids, the nodal maximum is of the same intensity as the “new” and “old” maxima, but is of a somewhat shorter duration than these two maxima. A similar study of the activity curve of all observed Perseid meteors (i.e. independent of apparent magnitude) shows the same multi-peak structure, but with slightly less pronounced peaks. In a previous study of the Perseid activity curve based on 605 photographic Perseid orbits obtained in various two-station programs 1937–1985 the multi-peak structure can be recognised in a number versus solar longitude diagram (Lindblad and Porubcan, 1994. Planet Space Sci. 42, 117–122.). The various peaks in the photographic data are located at the same solar longitudes as in the visual data. This agreement between the results of the present long-term visual study and a long-term photographic study of the Perseid activity curve strongly supports our conclusions as to the multi-peak structure of the Perseid shower.
The Ulysses spacecraft is orbiting the Sun on a highly inclined ellipse (i = 79°). After its Jupiter flyby in 1992 at a heliocentric distance of 5.4 AU, the spacecraftreapproached the inner solar system, flew over the Suns south polar region in September 1994,crossed the ecliptic plane at a distance of 1.3 AU in March 1995, and flew over the Suns northpolar region in July 1995. We report on dust impact data obtained with the dust detector onboardUlysses between January 1993 and December 1995. We publish and analyse the complete dataset of 509 recorded impacts of dust particles with masses between 10−16 g–10−7 g. Together with 968 dust impacts from launch until the end of 1992 published earlier (Grün et al., 1995c), information about 1477 particles detected with theUlysses sensor between October 1990 and December 1995 is now available. The impact ratemeasured between 1993 and 1995 stayed relatively constant at about 0.4 impacts per day andvaried by less than a factor of ten. Most of the impacts recorded outside about 3.5 AU arecompatible with particles of interstellar origin. Two populations of interplanetary particles havebeen recognized: big micrometer-sized particles close to the ecliptic plane and smallsub-micrometer-sized particles at high ecliptic latitudes. The observed impact rate is comparedwith a model for the flux of interstellar dust particles which gives relatively good agreement withthe observed impact rate. No change in the instruments noise characteristics or degradation of thechanneltron could be revealed during the three-year period.
Visual observations of Perseid meteors carried out in 1953–83 at the Onsala Space Observatory are analyzed to study the fine structure of the Perseid meteor stream maximum. Observed hourly rates are corrected for weather conditions and to a zenithal value. The Perseid activity curve is studied (1) for all observed Perseids, (2) for Perseids of app. magnitude 2.0 or brighter. The activity curve for both data sets shows two main peaks, one at solar long. 138.65° (1950.0) , very near to the node of the parent comet (Swift–Tuttle) , and a second peak at 139.42°, corresponding to the traditional maximum of the shower. A third, less conspicuous peak at 138.96° is also evident in the data. This peak could possibly be an early indication of the so-called new maximum of the Perseid stream. The detection of a well-defined peak in rates very near to the node of the parent comet is important since the position of the Perseid visual maximum usually quoted in the literature deviates from the cometary node by almost 1° in solar longitude.
Dust measurements have been obtained with the dust detector onboard the Galileo spacecraft inside a distance of about 60RJ from Jupiter (Jupiter radius, RJ = 71,492 km) during two periods of about 8 days around Galileo's closest approaches to Ganymede on 27 June and on 6 Sept 1996. The impact rate of submicrometer‐sized particles fluctuated by a factor of several hundred with a period of about 10 hours, implying that their trajectories are strongly affected by the interaction with the Jovian magnetic field. Concentrations of small dust impacts were detected at the times of Ganymede closest approaches that could be secondary ejecta particles generated upon impact of other particles onto Ganymede's surface. Micrometer‐sized dust particles, which could be on bound orbits about Jupiter, are concentrated in the inner Jovian system inside about 20RJ from Jupiter.
Identical in situ dust detectors are flown on board the Galileo and Ulysses spacecraft. They record impacts of micrometeoroids in the ecliptic plane at heliocentric distances from 0.7 to 5.4 AU and in a plane almost perpendicular to the ecliptic from -79 deg to +79 deg ecliptic latitude. The combination of both Ulysses and Galileo measurements yields information about the radial and latitudinal distributions of micron- and sub-micron-sized dust in the Solar System. Two types of dust particles were found to dominate the dust flux in interplanetary space. Interplanetary micrometeoroids covering a wide mass range from 10^-16 to 10^-6 g are recorded mostly inside 3 AU and at latitudes below 30 deg. Interstellar grains with masses between 10^-14 and 10^-12 g have been positively identified outside 3 AU near the ecliptic plane and outside 1.8 AU at high ecliptic latitudes (>50 deg). Interstellar grains move on hyperbolic trajectories through the planetary system and constitute the dominant dust flux (1.5 x 10^-4 m^-2 sec^-1) in the outer Solar System and at high ecliptic latitudes. To compare and analyze the Galileo and Ulysses data sets, a new model is developed based on J. Geophys. Res. 98, 17029-17048, Divine's (1993, ``five populations of interplanetary meteoroids'' model. Both models describe the interplanetary meteoroid environment in terms of dust populations on distinct orbits. Taking into account the measured velocities and the effect of radiation pressure on small particles (described by the ratio of radiation pressure force to gravity, beta), we define four populations of meteoroids on elliptical orbits and one population on hyperbolic orbit that can fit the micrometeoroid flux observed by Galileo and Ulysses. Micrometeoroids with masses greater than 10^-10 g and negligible radiation pressure (beta = 0) orbit the Sun on low to moderately eccentric orbits and with low inclinations (<=30 deg). Populations of smaller particles with mean masses of 10^-11 g (beta = 0.3), 10^-13 g (beta = 0.8), and 5 x 10^-15 g (beta = 0.3), respectively, have components with high eccentricities and have increasingly wider inclination distributions with decreasing mass. Similarities among the orbit distributions of the small particle populations on bound orbits suggest that all are genetically related and are part of an overall micrometeoroid complex that prevails in the inner Solar System. The high-eccentricity component of the small particle populations may actually be beta-meteoroids which are not well characterized by our measurements. Our modeling suggests further that the interstellar dust flux is not reduced at Ulysses' perihelion distance (1.3 AU) and that it contributes about 30% of the total dust flux observed there. (Less)
About a hundred dust impacts per day were detected during the first week in December 1995 by Galileo during its approach to Jupiter. These impacts were caused by submicrometer-sized particles that were just above the detection limit. After the closest approach to Io on 7 December, impacts of these small particles ceased. This effect is expected for dust grains emitted from Io that exit the field of view of the instrument after the flyby. The impact rate of bigger micrometer-sized dust grains continued to increase toward Jupiter. These dust particles are in orbit about Jupiter or are interplanetary grains that are gravitationally concentrated near Jupiter.
THE Ulysses spacecraft detected streams of sub-micrometre-sized dust particles as it approached Jupiter in 1992(1,2), Although interplanetary space was known to contain dust, the presence of discrete streams was completely unexpected, The directions from which the dust grains struck the spacecraft strongly suggested that the source lay somewhere within the Jupiter system, Three origins were proposed, the comet Shoemaker-Levy 9 (ref, 3), Jupiter's gossamer ring(4), and the volcanoes on Io(5), but there was no definitive evidence for or against any of the options. Here we report the detection by the Galileo spacecraft of even more intense dust streams-including three intense dust storms of month-long duration, with impact rates up to 10 times higher than those observed by Ulysses, Our analysis of the data confirms that the dust streams originate near Jupiter; rye are able to rule out a cometary origin, but cannot yet determine conclusively whether the dust comes from Io or the ring.
A study of the Kappa Cygnid and other minor streams of the August epoch is presented based on a computer search in a sample of 3518 photographic meteoroid orbits. Four different meteoroid streams with radiants in Cygnus, Draco and Lyra, were found. Three of these: the Kappa Cygnids, the Alpha Lyrids and the Zeta Draconids are identified with meteor showers reported by nineteenth century visual observers. The fourth stream, the August Lyrids, consists of six meteors with radiants in Lyra centered on α = 277°.6,δ = 46°.2. No previous visual reports of this stream have been found. It is interesting to note that all four meteoroid streams are coincident in time; their orbits are all of short period and they all have very nearly the same orientation of semi-major axis.