Author
Veerle Sterken
Other affiliations: Max Planck Society, Empik, International Space Science Institute ...read more
Bio: Veerle Sterken is an academic researcher from University of Bern. The author has contributed to research in topics: Cosmic dust & Solar System. The author has an hindex of 18, co-authored 47 publications receiving 862 citations. Previous affiliations of Veerle Sterken include Max Planck Society & Empik.
Papers
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University of California, Berkeley1, United States Naval Research Laboratory2, Lawrence Berkeley National Laboratory3, Goethe University Frankfurt4, State University of New York at Plattsburgh5, Jacobs Engineering Group6, Heidelberg University7, Carnegie Institution for Science8, Field Museum of Natural History9, University of Leicester10, University of Washington11, University of Kent12, Ghent University13, University of New Mexico14, European Synchrotron Radiation Facility15, University of Chicago16, Washington University in St. Louis17, Max Planck Society18, International Space Science Institute19, Natural History Museum20, Argonne National Laboratory21, École normale supérieure de Lyon22, university of lille23, Ames Research Center24, University of Stuttgart25, Jet Propulsion Laboratory26
TL;DR: The Stardust Interstellar Dust Collector captured seven particles and returned to Earth for laboratory analysis have features consistent with an origin in the contemporary interstellar dust stream and more than 50 spacecraft debris particles were also identified as discussed by the authors.
Abstract: Seven particles captured by the Stardust Interstellar Dust Collector and returned to Earth for laboratory analysis have features consistent with an origin in the contemporary interstellar dust stream. More than 50 spacecraft debris particles were also identified. The interstellar dust candidates are readily distinguished from debris impacts on the basis of elemental composition and/or impact trajectory. The seven candidate interstellar particles are diverse in elemental composition, crystal structure, and size. The presence of crystalline grains and multiple iron-bearing phases, including sulfide, in some particles indicates that individual interstellar particles diverge from any one representative model of interstellar dust inferred from astronomical observations and theory.
176 citations
University College London1, Planetary Science Institute2, European Space Agency3, Queen Mary University of London4, University of Leicester5, Lancaster University6, University of Wisconsin-Madison7, Jet Propulsion Laboratory8, Cornell University9, University of Grenoble10, Centre national de la recherche scientifique11, Rutherford Appleton Laboratory12, Braunschweig University of Technology13, Delft University of Technology14, University of Liège15, Maynooth University16, Johns Hopkins University Applied Physics Laboratory17, University of Orléans18, Max Planck Society19, Goddard Space Flight Center20, National and Kapodistrian University of Athens21, University of California, Berkeley22, Southwest Research Institute23, Imperial College London24, INAF25, University of Oxford26, University of California, Santa Cruz27, University of Colorado Boulder28, University of Idaho29, Tel Aviv University30, Heidelberg University31, University of Liverpool32, University of Iowa33, University of Southampton34, Royal Observatory of Belgium35, University of Stuttgart36, Bundeswehr University Munich37, university of lille38, Institut de Physique du Globe de Paris39, University of Vienna40, Austrian Academy of Sciences41, National University of Ireland42, Space Science Institute43, University of Cologne44, Université de Namur45, University of Reading46, Pierre-and-Marie-Curie University47, University of California, Los Angeles48, University of the Basque Country49, University of Virginia50, Lunar and Planetary Institute51, Academy of Athens52, University of Potsdam53, International Space Science Institute54, University of Nantes55
TL;DR: In this article, the authors describe the science case for an orbital mission to Uranus with an atmospheric entry probe to sample the composition and atmospheric physics in Uranus' atmosphere, and discuss the technical challenges for such a mission.
75 citations
TL;DR: In this paper, the authors characterize the flow of ISD through the solar system using simulations of the dust trajectories and derive the densities, fluxes, and directionalities from the trajectory simulations, which can also be used for predicting dust fluxes for different space missions or planets.
Abstract: Context. Interstellar dust (ISD) is a major component in the formation and evolution of stars, stellar systems, and planets. Astronomical observations of interstellar extinction and polarization, and of the infrared emission of the dust, are the most commonly used technique for characterizing interstellar dust. Besides this, the interstellar dust from the local interstellar cloud enters the solar system owing to the relative motion of the Sun with respect to this cloud. Once in the solar system, in-situ observations can be made by spacecraft using impact ionization detectors and time-of-flight spectrometers like the ones flown on the Cassini , Ulysses , and Galileo , spacecrafts. Also a sample return can be done, as in the Stardust mission. Once in the solar system, the trajectories of these dust grains are shaped by gravitational, solar radiation pressure, and Lorentz forces. The Lorentz forces result from the interaction of the charged dust particles with the interplanetary magnetic field. The ISD densities in the solar system thus depend both on the location in the solar system and on time, correlated to the solar cycle.Aims. This paper aims at giving the reader insight into the flow patterns of ISD when it moves through the solar system. This is useful for designing future in-situ or sample return missions or for knowing whether for specific missions, simplified assumptions can be used for the dust flux and direction, or whether full simulations are needed. Methods. We characterize the flow of ISD through the solar system using simulations of the dust trajectories. We start from the simple case without Lorentz forces and expand to the full simulation. We pay attention to the different ways of modeling the interplanetary magnetic field and discuss the influence of the dust parameters on the resulting flow patterns. Dust densities, fluxes, and directionalities are derived from the trajectory simulations. Different graphics representations are used to gain insight into the flow patterns. As an illustration of how the model can be used, we predict the fluxes and directionalities of the ISD for the Cassini mission. Results. The characteristics of the flow of ISD through the solar system have been investigated to gain insight in the patterns of the flow. The modeling can also be used for predicting dust fluxes for different space missions or planets, and for understanding spacecraft measurements, such as those from Ulysses , Cassini , and Stardust.
69 citations
Technische Universität München1, European Space Agency2, University of Stuttgart3, Université Paris-Saclay4, State University of New York at Plattsburgh5, University of Toulouse6, University of Paris7, University of Colorado Boulder8, Tohoku University9, University of California, Berkeley10, University of Bern11, Spanish National Research Council12
TL;DR: In this paper, the distribution of interplanetary dust and meteoroids in the solar system is studied. But the authors focus on the current state and the dynamical behavior of the Solar system.
Abstract: Interplanetary dust particles and meteoroids mostly originate from comets and asteroids. Understanding their distribution in the Solar system, their dynamical behavior and their properties, sheds light on the current state and the dynamical behavior of the Solar system. Dust particles can endanger Earth-orbiting satellites and deep-space probes, and a good understanding of the spatial density and velocity distribution of dust and meteoroids in the Solar system is important for designing proper spacecraft shielding. The study of interplanetary dust and meteoroids provides clues to the formation of the Solar system. Particles having formed 4.5 billion years ago can survive planetary accretion and those that survived until now did not evolve significantly since then. Meteoroids and interplanetary dust can be observed by measuring the intensity and polarization of the zodiacal light, by observing meteors entering the Earth’s atmosphere, by collecting them in the upper atmosphere, polar ices and snow, and by detecting them with in-situ detectors on space probes.
55 citations
TL;DR: In this article, the authors analyzed the entire data set from 16 yr of Ulysses interstellar dust measurements in interplanetary space and found a gas-to-dust mass ratio in the local interstellar cloud of and a dust density of (2.1 ± 0.6) × 10−24 kg m−3.
Abstract: In the early 1990s, contemporary interstellar dust penetrating deep into the heliosphere was identified with the in situ dust detector on board the Ulysses spacecraft. Between 1992 and the end of 2007 Ulysses monitored the interstellar dust stream. The interstellar grains act as tracers of the physical conditions in the local interstellar medium (ISM) surrounding our solar system. Earlier analyses of the Ulysses interstellar dust data measured between 1992 and 1998 implied the existence of a population of "big" interstellar grains (up to 10−13 kg). The derived gas-to-dust-mass ratio was smaller than the one derived from astronomical observations, implying a concentration of interstellar dust in the very local ISM. In this paper we analyze the entire data set from 16 yr of Ulysses interstellar dust measurements in interplanetary space. This paper concentrates on the overall mass distribution of interstellar dust. An accompanying paper investigates time-variable phenomena in the Ulysses interstellar dust data, and in a third paper we present the results from dynamical modeling of the interstellar dust flow applied to Ulysses. We use the latest values for the interstellar hydrogen and helium densities, the interstellar helium flow speed of , and the ratio of radiation pressure to gravity, β, calculated for astronomical silicates. We find a gas-to-dust mass ratio in the local interstellar cloud of and a dust density of (2.1 ± 0.6) × 10−24 kg m−3. For a higher inflow speed of the gas-to-dust mass ratio is 20% higher, and, accordingly, the dust density is lower by the same amount. The gas-to-dust mass ratio derived from our new analysis is compatible with the value most recently determined from astronomical observations. We confirm earlier results that the very local ISM contains "big" (i.e., ≈1 μm sized) interstellar grains. We find a dust density in the local ISM that is a factor of three lower than values implied by earlier analyses.
52 citations
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15 Mar 1979
TL;DR: In this article, the experimental estimation of parameters for models can be solved through use of the likelihood ratio test, with particular attention to photon counting experiments, and procedures presented solve a greater range of problems than those currently in use, yet are no more difficult to apply.
Abstract: Many problems in the experimental estimation of parameters for models can be solved through use of the likelihood ratio test. Applications of the likelihood ratio, with particular attention to photon counting experiments, are discussed. The procedures presented solve a greater range of problems than those currently in use, yet are no more difficult to apply. The procedures are proved analytically, and examples from current problems in astronomy are discussed.
1,748 citations
TL;DR: In this article, the authors consider the extensive experimental and computer simulation studies that have been performed over the past several decades on what the nature of the primary damage is, and provide alternatives to the current international standard for quantifying this energetic particle damage, the Norgett-Robinson-Torrens displacements per atom (NRT-dpa) model for metals.
334 citations
Free University of Berlin1, Heidelberg University2, Leibniz Association3, University of Nantes4, Southwest Research Institute5, California Institute of Technology6, University of Colorado Boulder7, University of Stuttgart8, Johns Hopkins University Applied Physics Laboratory9, University of Oulu10, Leipzig University11
TL;DR: The detection of complex organic molecules with masses higher than 200 atomic mass units in ice grains emitted from Enceladus indicates the presence of a thin organic-rich layer on top of the moon’s subsurface ocean.
Abstract: Saturn’s moon Enceladus harbours a global water ocean1, which lies under an ice crust and above a rocky core2. Through warm cracks in the crust3 a cryo-volcanic plume ejects ice grains and vapour into space4–7 that contain materials originating from the ocean8,9. Hydrothermal activity is suspected to occur deep inside the porous core10–12, powered by tidal dissipation13. So far, only simple organic compounds with molecular masses mostly below 50 atomic mass units have been observed in plume material6,14,15. Here we report observations of emitted ice grains containing concentrated and complex macromolecular organic material with molecular masses above 200 atomic mass units. The data constrain the macromolecular structure of organics detected in the ice grains and suggest the presence of a thin organic-rich film on top of the oceanic water table, where organic nucleation cores generated by the bursting of bubbles allow the probing of Enceladus’ organic inventory in enhanced concentrations.
263 citations
TL;DR: The THEMIS (The Heterogeneous dust Evolution Model for Interstellar Solids) model as discussed by the authors is based upon a core model that was developed to explain the dust extinction and emission in the diffuse interstellar medium.
Abstract: Here we introduce the interstellar dust modelling framework THEMIS (The Heterogeneous dust Evolution Model for Interstellar Solids), which takes a global view of dust and its evolution in response to the local conditions in interstellar media. This approach is built upon a core model that was developed to explain the dust extinction and emission in the diffuse interstellar medium. The model was then further developed to self-consistently include the effects of dust evolution in the transition to denser regions. The THEMIS approach is under continuous development and currently we are extending the framework to explore the implications of dust evolution in HII regions and the photon-dominated regions associated with star formation. We provide links to the THEMIS, DustEM and DustPedia websites where more information about the model, its input data and applications can be found.
204 citations
TL;DR: The THEMIS (The Heterogeneous dust Evolution Model for Interstellar Solids) model as discussed by the authors is based on a core model that was developed to explain the dust extinction and emission in the diffuse interstellar medium.
Abstract: Here we introduce the interstellar dust modelling framework THEMIS (The Heterogeneous dust Evolution Model for Interstellar Solids), which takes a global view of dust and its evolution in response to the local conditions in interstellar media. This approach is built upon a core model that was developed to explain the dust extinction and emission in the diffuse interstellar medium. The model was then further developed to self-consistently include the effects of dust evolution in the transition to denser regions. The THEMIS approach is under continuous development and we are currently extending the framework to explore the implications of dust evolution in HII regions and the photon-dominated regions associated with star formation. We provide links to the THEMIS, DustEM and DustPedia websites where more information about the model, its input data and applications can be found.
199 citations