[Show abstract][Hide abstract] ABSTRACT: The Stardust mission returned cometary, interplanetary and (probably) interstellar dust in 2006 to Earth that have been analysed in Earth laboratories worldwide. Results of this mission have changed our view and knowledge on the early solar nebula. The Rosetta mission is on its way to land on comet 67P/Churyumov-Gerasimenko and will investigate for the first time in great detail the comet nucleus and its environment starting in 2014. Additional astronomy and planetary space missions will further contribute to our understanding of dust generation, evolution and destruction in interstellar and interplanetary space and provide constraints on solar system formation and processes that led to the origin of life on Earth. One of these missions, SARIM-PLUS, will provide a unique perspective by measuring interplanetary and interstellar dust with high accuracy and sensitivity in our inner solar system between 1 and 2 AU. SARIM-PLUS employs latest in-situ techniques for a full characterisation of individual micrometeoroids (flux, mass, charge, trajectory, composition) and collects and returns these samples to Earth for a detailed analysis. The opportunity to visit again the target comet of the Rosetta mission 67P/Churyumov-Gerasimeenternko, and to investigate its dusty environment six years after Rosetta with complementary methods is unique and strongly enhances and supports the scientific exploration of this target and the entire Rosetta mission. Launch opportunities are in 2020 with a backup window starting early 2026. The comet encounter occurs in September 2021 and the reentry takes place in early 2024. An encounter speed of 6 km/s ensures comparable results to the Stardust mission.
No preview · Article · Apr 2012 · Experimental Astronomy
[Show abstract][Hide abstract] ABSTRACT: 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.
[Show abstract][Hide abstract] ABSTRACT: A new computer code is developed for the ESA meteoroid model to predict
spatial number densities, fluxes and impact velocities of the meteoroids
on an arbitrary target in the Solar system and near Earth. It implements
a new integration scheme that is, unlike its predecessors, free of
singularities, and much faster in calculating narrowly collimated
fluxes, i.e. particularly good for simulations of measurements with the
dust detectors having narrow fields of view, or for making
high-resolution maps of sporadic meteor radiants. The new code provides
a lot of extra flexibility in making flux predictions as functions of
particle mass, size, incidence angle and velocity. It is accompanied by
a modern portable graphic user interface (GUI) that is a full-featured
front for the computational engine. It allows to set most of the input
parameters, run the computations, and view and save the results in the
form of plots or text tables.
[Show abstract][Hide abstract] ABSTRACT: The orbital distributions of meteoroids in interplanetary space are revised in the ESA meteoroid model. In the present update, the chemical composition of the meteoroids is simulated in more detail than in the previous meteoroid models. Silicate and carbonaceous fractions are introduced for all meteoroid populations, and in addition to asteroids and Jupiter-crossing comets, comet 2P/Encke is added as a source. The orbital evolution under planetary gravity, Poynting-Robertson effect and mutual collisions is simulated using analytical approximations. Infrared observations of the zodiacal cloud by the COBE DIRBE instrument, in situ flux measurements by the dust detectors on board Galileo, Ulysses, Pioneer 11 and Helios-1 spacecraft, and the crater size distributions on lunar rock samples retrieved by the Apollo missions are incorporated in the model.
[Show abstract][Hide abstract] ABSTRACT: Analyses of the cosmic microwave background (CMB) radiation maps made by the Wilkinson Microwave Anisotropy Probe (WMAP) have revealed anomalies not predicted by the standard inflationary cosmology. In particular, the power of the quadrupole moment of the CMB fluctuations is remarkably low, and the quadrupole and octopole moments are aligned mutually and with the geometry of the Solar system. It has been suggested in the literature that microwave sky pollution by an unidentified dust cloud in the vicinity of the Solar system may be the cause for these anomalies. In this paper, we simulate the thermal emission by clouds of spherical homogeneous particles of several materials. Spectral constraints from the WMAP multi-wavelength data and earlier infrared observations on the hypothetical dust cloud are used to determine the dust cloud's physical characteristics. In order for its emissivity to demonstrate a flat, CMB-like wavelength dependence over the WMAP wavelengths (3 through 14 mm), and to be invisible in the infrared light, its particles must be macroscopic. Silicate spheres from several millimetres in size and carbonaceous particles an order of magnitude smaller will suffice. According to our estimates of the abundance of such particles in the Zodiacal cloud and trans-neptunian belt, yielding the optical depths of the order of 1E-7 for each cloud, the Solar-system dust can well contribute 10 microKelvin (within an order of magnitude) in the microwaves. This is not only intriguingly close to the magnitude of the anomalies (about 30 microKelvin), but also alarmingly above the presently believed magnitude of systematic biases of the WMAP results (below 5 microKelvin) and, to an even greater degree, of the future missions with higher sensitivities, e.g. PLANCK. Comment: 33 pages, 9 figures, 1 table. The Astrophysical Journal, 2009, accepted
Preview · Article · Oct 2009 · The Astrophysical Journal
[Show abstract][Hide abstract] ABSTRACT: The Ulysses spacecraft has been orbiting the Sun on a highly inclined ellipse (i=79∘, perihelion distance 1.3 AU, aphelion distance 5.4 AU) since it encountered Jupiter in February 1992. Since then it has made almost three revolutions about the Sun. Here we report on the final three years of data taken by the on-board dust detector. During this time, the dust detector recorded 609 dust impacts of particles with masses , bringing the mission total to 6719 dust data sets. The impact rate varied from a low value of 0.3 per day at high ecliptic latitudes to 1.5 per day in the inner solar system. The impact direction of the majority of impacts between 2005 and 2007 is compatible with particles of interstellar origin; the rest are most likely interplanetary particles. We compare the interstellar dust measurements from 2005/2006 with the data obtained during earlier periods (1993/1994) and (1999/2000) when Ulysses was traversing the same spatial region at southern ecliptic latitudes but the solar cycle was at a different phase. During these three intervals the impact rate of interstellar grains varied by more than a factor of two. Furthermore, in the two earlier periods the grain impact direction was in agreement with the flow direction of the interstellar helium while in 2005/2006 we observed a shift in the approach direction of the grains by approximately 30∘ away from the ecliptic plane. The reason for this shift remains unclear but may be connected with the configuration of the interplanetary magnetic field during solar maximum. We also find that the dust measurements are in agreement with the interplanetary flux model of Staubach et al. (1997) which was developed to fit a 5-year span of Ulysses data.
Full-text · Article · Aug 2009 · Planetary and Space Science
[Show abstract][Hide abstract] ABSTRACT: The existence of a cloud of dust particles that pervades interplanetary space has long been known from the presence of its optical manifestation, the zodiacal light. This dim glow, best seen about one hour after sunset or before sunrise, when its brighter inner parts are above the horizon, was one of the first phenomena recognized as originating in interplanetary space. Given its conspicious appearance at low geographic latitudes (Fig. 5.1) one may wonder that there were no records of it until the end of the 17th century, when Cassini (1683) announced its discovery and offered the correct explanation: it is sunlight, scattered off myriads of small particles orbiting the sun. Towards the sun it continues with increasing brightness; the innermost parts can be seen during solar eclipses or from space as the F component (showing Fraunhofer lines) of the solar corona. Photometric measurements have shown that it covers the whole sky, but it is brightest in a band along the ecliptic. Around the antisolar point it brightens again; this Gegenschein can be seen by the naked eye under exceptional conditions.
[Show abstract][Hide abstract] ABSTRACT: Several models for the sporadicmeteoroid background have been developed
over the last two decades. These include, among others, the Divine, the
Staubach and the Dikarev model. They cover mass ranges from 10-18 g to 1
g typically and are applicable for model-specific heliocentric distance
ranges between 0.1 and 20 AU. At 1 AU from the Sun in the ecliptic
plane, averaged fluxes (over directions and velocities) are tuned to the
well established interplanetary model by Grün et al. (1985).
However, in many respects thesemodels differ considerably, and our
comparison of flux predictions near Earth from existing models shows a
clear need for additional measurements and simulations in order to
derive a reliable model for the population of interplanetary and
[Show abstract][Hide abstract] ABSTRACT: Over the last decade several new models for the sporadic interplanetary meteoroid flux have been developed. These include the Divine-Staubach and the Dikarev model. They typically cover mass ranges from 10−18 g to 1 g and are applicable for model specific Sun distance ranges between 0.1 AU and 20 AU Near 1 AU averaged fluxes (over direction and velocities) for all these models are tuned to the well established interplanetary model by Grün et al. However, in many respects these models differ considerably. Examples are the velocity and directional distributions and the assumed meteoroid sources. In this paper flux predictions by the various models to Earth orbiting spacecraft are compared. Main differences are presented and analysed. The persisting differences even for near Earth space can be seen as surprising in view of the numerous ground based (optical and radar) and in situ (captured Inter Stellar Dust Particles, in situ detectors and analysis of retrieved hardware) measurements and simulations.
Full-text · Article · Jun 2008 · Earth Moon and Planets
[Show abstract][Hide abstract] ABSTRACT: Saturn's moon Rhea had been considered massive enough to retain a thin, externally generated atmosphere capable of locally
affecting Saturn's magnetosphere. The Cassini spacecraft's in situ observations reveal that energetic electrons are depleted
in the moon's vicinity. The absence of a substantial exosphere implies that Rhea's magnetospheric interaction region, rather
than being exclusively induced by sputtered gas and its products, likely contains solid material that can absorb magnetospheric
particles. Combined observations from several instruments suggest that this material is in the form of grains and boulders
up to several decimetres in size and orbits Rhea as an equatorial debris disk. Within this disk may reside denser, discrete
rings or arcs of material.
[Show abstract][Hide abstract] ABSTRACT: We report an analysis of the Cosmic Dust Analyzer data obtained during
the interplanetary cruise of the Cassini spacecraft between Jupiter and
Saturn. The data cover the time period between the Jupiter flyby and the
Saturn orbit insertion. Seventeen dust particles on bound and unbound
(hyperbolic) orbits were also detected, with sizes in the submicrometer
to the micrometer range. Our measurements are compared with the Pioneer
dust data obtained 30 years ago and model predictions. Particles on
bound orbits have low eccentricities and low inclinations. Possible
sources are short-period Jupiter family comets and circumsolar dust. The
impactors on hyperbolic orbits were identified as being most likely
interstellar dust (ISD) grains with a radius of ≈0.4 μm. The
corresponding flux of ≈2 × 10-5 m-2
s-1 is in a very good agreement with the ISD flux
measurements performed by the Ulysses spacecraft over the same time
No preview · Article · Jul 2007 · Journal of Geophysical Research Atmospheres
[Show abstract][Hide abstract] ABSTRACT: Analyses of the cosmic microwave background (CMB) radiation maps produced by the Wilkinson Microwave Anisotropy Probe (WMAP)
have revealed anomalies not predicted by the standard cosmological theory. It has been suggested that a dust cloud in the
vicinity of the Solar system may be the cause for these anomalies. In this paper, the thermal emission by particles from two
known interplanetary meteoroid complexes is tested against the CMB maps. Conclusions are drawn based on the geometry of cloud
projections onto the WMAP sky whether these clouds are likely to explain the observed anomaly. The smooth background Zodiacal
cloud and one of the Taurid meteor complex branches do not explain the WMAP anomaly.
Preview · Article · Jun 2007 · Earth Moon and Planets
[Show abstract][Hide abstract] ABSTRACT: A dust astronomy mission aims at the simultaneous measurement of the
origin and the chemical composition of individual dust grains in space.
By distinguishing interstellar from interplanetary dust of cometary or
asteroidal origin based on their trajectories and comparing their
composition important clues on processes in the early solar system can
be obtained. The dust observatory mission "Cosmic DUNE" has been defined
to reach this goal with newly developed dust instrumentation. A dust
trajectory sensor has been developed which is capable of obtaining
precision trajectories of sub-micron sized particles in space. A new
high mass resolution dust analyzer of 0.1 m^2 impact area can cope with
the low fluxes expected in interplanetary space. With these instruments
both novel dust measurements in low-Earth orbit and improved dust
collection and sample return schemes are achievable.
[Show abstract][Hide abstract] ABSTRACT: Faint rings of micrometre-sized dust particles embrace many planets in the Solar system. As a rule, they are replenished by ejecta from embedded atmosphereless moons. On a number of occasions, the ejecta are generated by hypervelocity meteoroid impacts into the moons. Small ejecta fragments are then swiftly shifted into rings by an array of non-gravitational forces, e.g. radiation pressure or plasma drag. A significant fraction of ejecta mass, however, is contained in relatively big, multi-micrometre fragments which are subject to gravity only. Having escaped from the satellite, they stay close to its orbit and form a belt around planet. This belt is itself a source of ring dust through collisional disruption of its particles. Here the contributions of belts to the respective rings are estimated for selected satellites of Jupiter and Saturn. The belts under review could supply substantially more dust to rings than the direct ejecta from satellites and should be taken into account when estimating ring dust budgets. The belts are very difficult to observe, however, and some of them remain a theoretical proposition. We find an appealing evidence for the belts due to Amalthea and Thebe around Jupiter, and for the belt due to Enceladus around Saturn.
No preview · Article · Aug 2006 · Planetary and Space Science
[Show abstract][Hide abstract] ABSTRACT: The putative dust belts of Mars, a thin equatorial Phobos ring and a thick tilted Deimos torus, whose existence was predicted several decades ago, remain undiscovered. The previous attempt of direct observational detection, undertaken with the Hubble Space Telescope (HST) during the Mars equatorial plane crossing in May 2001, set an upper limit on the normal optical depth to ∼3×10-8 for the Phobos ring and ∼10-7 for the Deimos torus. This paper analyzes possible reasons for non-detection of the belts and focuses on the next, and the last for three decades to come, natural opportunity to search for the dust belts during the Mars ring plane crossing in December 2007. We have extended our dynamical models to predict the appearance of both dust belts and to estimate the distribution of their optical depth and brightness. Our new calculations show that at least the Deimos dust torus may have escaped HST detection in 2001 only marginally. A thoroughly prepared observational attempt in 2007 with HST, Keck or another comparable telescope will have good chances to discover the Deimos torus, if a detector has a sensitivity by about one order of magnitude better than the one used in 2001. Photometric detection of the Phobos ring appears to be more difficult.
Full-text · Article · Aug 2006 · Planetary and Space Science
[Show abstract][Hide abstract] ABSTRACT: In July 2004 the Cassini–Huygens mission reached the Saturnian system and started its orbital tour. A total of 75 orbits will be carried out during the primary mission until August 2008. In these four years Cassini crosses the ring plane 150 times and spends approx. 400 h within Titan's orbit. The Cosmic Dust Analyser (CDA) onboard Cassini characterises the dust environment with its extended E ring and embedded moons. Here, we focus on the CDA results of the first year and we present the Dust Analyser (DA) data within Titan's orbit. This paper does investigate High Rate Detector data and dust composition measurements. The authors focus on the analysis of impact rates, which were strongly variable primarily due to changes of the spacecraft pointing. An overview is given about the ring plane crossings and the DA counter measurements. The DA dust impact rates are compared with the DA boresight configuration around all ring plane crossings between June 2004 and July 2005. Dust impacts were registered at altitudes as high as 100 000 km above the ring plane at distances from Saturn between 4 and 10 Saturn radii. In those regions the dust density of particles bigger than can reach values of .
No preview · Article · Aug 2006 · Planetary and Space Science
[Show abstract][Hide abstract] ABSTRACT: The Ulysses spacecraft has been orbiting the Sun on a highly inclined ellipse (i = 79 degrees, perihelion distance 1.3 AU, aphelion distance 5.4 AU) 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(-16) g <= M <= 10(-7) g. Together with. 1695 dust impacts recorded between launch of Ulysses and the end of 1999 published earlier (Grain, E., Baguhl, M., Divine, N., Fechtig, H., Hamilton, D.P, Harmer, M.S., Kissel, J., Lindblad, B.A., Linkert, D., Linkert, G., Mann, L, 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; Kruger, H., Grun, E., Landgraf, M., Baguhl, M., Dermott, S.F., Fechtig, H., Gustafson, B.A., Hamilton, D.P., Harmer, M.S., Horanyi, M., Kissel, J., Lindblad, B., Linkert, D., Linkert, G., Mann, L, 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; Kruger, H., Grun, E., Landgraf, M., Dermott, S.F., Fechtig, H., Gustafson, B.A., Hamilton, D.P., Harmer, M.S., Horanyi, 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., Grun, E., Jehn, R., 1997. The meteoroid environment near Earth, Adv. Space Res. 19, 301-308.
No preview · Article · Aug 2006 · Planetary and Space Science
[Show abstract][Hide abstract] ABSTRACT: During Cassini's close flyby of Enceladus on 14 July 2005, the High Rate Detector of the Cosmic Dust Analyzer registered micron-sized
dust particles enveloping this satellite. The dust impact rate peaked about 1 minute before the closest approach of the spacecraft
to the moon. This asymmetric signature is consistent with a locally enhanced dust production in the south polar region of
Enceladus. Other Cassini experiments revealed evidence for geophysical activities near Enceladus' south pole: a high surface
temperature and a release of water gas. Production or release of dust particles related to these processes may provide the
dominant source of Saturn's E ring.
[Show abstract][Hide abstract] ABSTRACT: We present an analysis of the Cassini Cosmic Dust Analyzer (CDA) data obtained beyond Jupiter's orbit during the cruise phase preceding the Saturn Orbit Insertion phase (SOI) on July 1, 2004. In-situ dust measurements beyond 5 AU are crucial for understanding the various origins of the zodiacal cloud components. While a large number of in-situ and remote sensing observations (scattered light and infrared emission) allow a good characterization of the dust populations inside Jupiter's orbit, there are very few observations at larger heliocentric distances. In-situ dust measurements are best suited to study the dust complex at large heliocentric distances because of the lower signal-to-noise ratio and the difficulty of the inversion problem in case of remote sensing techniques. However, prior to the Cassini mission, the only in-situ dust data available beyond 5 AU have been obtained nearly 30 years ago by the meteoroid penetration detectors on-board the Pioneer 10 and Pioneer 11 spacecraft. Before presenting the CDA data analysis, we review the results obtained on the dust complex between Jupiter and Saturn prior to the Cassini mission. We conclude that CDA and Pioneer dust data can not be easily compared mainly because of measurement strategies involving different geometry. However, the highly sensitive CDA instrument provides a complementary picture to the Pioneer data thanks to a better characterization of individual particles.