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| Reformation of an oblique shock observed by Cluster |
| On 16 March 2005, the Cluster spacecraft crossed a shock almost at the transition between the quasi-perpendicular and quasi-parallel regimes (ThetaBn = 46°) preceded by an upstream low-frequency (~0.02 Hz in the spacecraft frame) wave train observed for more than 10 mn. The wave semicycle nearest to the shock was found to grow in time, steepen and reflect an increasing fraction of the incoming ions. This gives strong indication that this pulsation is becoming a new shock front, standing ~5lambdap upstream of the main front and growing to shock-like amplitude on a timescale of ~35 Omegap. Downstream of the main shock transition, remnants of an older front are found indicating that the reformation is cyclic. This provides a unique example where the dynamics of shock reformation can be sequentially followed. The process shares many characteristics with simulations of reforming quasi-parallel shocks. |
| Publication date: 25 Nov 2009 |
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| Cluster observations of energetic electron flux variations within the plasma sheet |
| The variability of energetic electron fluxes (>40 keV) within the plasma sheet is explored using measurements from the Cluster spacecraft from 2001 through 2005. Only cases where the spacecraft remains inside the plasma sheet throughout the event are considered. Interesting cases were found using a combination of automated methods and visual inspection. Events are classified into 4 main types: (1) plasma sheet empty of energetic electrons; (2) decreasing plasma sheet energetic electron fluxes; (3) increasing plasma sheet energetic electron fluxes; and (4) sharp (rising and falling) variations in plasma sheet energetic electron fluxes during a single plasma sheet crossing. Case studies are presented for each type of event. The time it takes to fill/empty the plasma sheet of energetic electrons is quantified based on these events. Extreme events, most of which are associated with enhanced geomagnetic activity, showed that energetic electrons in the plasma sheet can vary up to several orders of magnitude. Interestingly, the energetic electron fluxes inside the plasma sheet can still undergo rapid variations when the solar wind is calm and geomagnetic activity is low. |
| Publication date: 18 Nov 2009 |
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| Comparative Planetology: Transiting Exoplanet Science with JWST |
| The study of transiting exoplanets has provided most of the key data to date on the properties of exoplanets, such as direct estimates of their mass and radius (e.g.Charbonneau 2007), and spectral diagnostics of their atmospheres (e.g. Swain et al.
2008). The Hubble Space Telescope (HST) and Spitzer Space Telescope (SST) have both played lead roles in making the demanding, high S/N observations of light curves, and spectra of transiting exoplanets. Ground-based surveys have so far provided the candidate targets for space-based characterization studies. The study of transiting exoplanets requires the extraction of a differential signal from high S/N observations so
the James Webb Space Telescope (JWST), by virtue of its 25 m2 collecting area (~50x SST), will open up a new discovery space for transiting exoplanet science. Specifically, it
will enable the characterization of intermediate and low mass exoplanets. The goal of this white paper is to provide an informational briefing for the panel on the expected capabilities of JWST for observations of exoplanet transits, in particular the
characterization of transiting lower mass planets (d MNep). |
| Publication date: 15 Nov 2009 |
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| First Light and Reionization: open questions in the post-JWST era |
| The aim of this paper is to outline the expected JWST performance in addressing first
light and reionization science questions that are found to be of interest today. These are
some of the most challenging and interesting questions in modern astronomy, and are key
drivers for the design of the JWST. Nevertheless, because these early epochs are difficult
to observe, even JWST is unlikely to provide complete answers. |
| Publication date: 15 Nov 2009 |
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| JWST Study of Planetary Systems and Solar System Objects |
| Determination of the physical and chemical properties of planetary systems is the main
objective of the planetary systems and the origins of life scientific theme of the James
Webb Space Telescope (JWST). This white paper summarizes the missions capabilities
for direct detection and study of exoplanets and circumstellar material (>0.1" from parent
star), planets and other objects in our own Solar System, and corresponding scientific
advances expected from JWST in the next decade. |
| Publication date: 15 Nov 2009 |
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| Stellar Populations with JWST: the Beginning and the End |
| We discuss the recent progress on stellar populations provided by the influx of high
sensitivity infrared photometry measurements using the Spitzer SAGE survey of the
Large Magellanic Cloud as an example. We discuss the important role JWST will play in
expanding such studies out to the local volume of galaxies (~10 Mpc) and its synergy
with concurrent missions. In addition to observational capabilities, we will need
theoretical tools to further this field in the next decade. |
| Publication date: 15 Nov 2009 |
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| The Scientific Capabilities of the James Webb Space Telescope |
| The James Webb Space Telescope is a large (25 m2), cold (<50 K), infrared (IR)-optimized space observatory that will be launched
during 2013. It is the successor to the Hubble and Spitzer Space Telescopes. The observatory has four instruments: a near-IR camera, a near-IR multi-object spectrograph, and a tunable filter
imager will operate within the wavelength range, 0.6 < l < 5.0 microns, while the mid-IR instrument
will provide both imaging and spectroscopy over the
5.0 < l < 28.5 microns spectrum. |
| Publication date: 15 Nov 2009 |
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| Imaging the Interaction of the Heliosphere with the Interstellar Medium from Saturn with Cassini |
| We report an all-sky image of energetic neutral atoms (ENAs) >6 kilo-electron volts produced by energetic protons occupying the region (heliosheath) between the boundary of the extended solar atmosphere and the local interstellar medium (LISM). The map obtained by the Ion and Neutral Camera (INCA) onboard Cassini reveals a broad belt of energetic protons whose nonthermal pressure is comparable to that of the local interstellar magnetic field. The belt, centered at ~260° ecliptic longitude extending from north to south and looping back through ~80°, appears to be ordered by the local interstellar magnetic field. The shape revealed by the ENA image does not conform to current models, wherein the heliosphere resembles a cometlike figure aligned in the direction of Sun's travel through the LISM. |
| Publication date: 13 Nov 2009 |
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| Technical Review Report - Plato |
| Reference: SRE-PA/2009.081 This technical review report for the Plato candidate mission presents the outcome of ESA's internal review of this M-class candidate mission in the Cosmic Vision 2015-2025 plan. The review was concluded at the end of the mission assessment phase and carried out in frame of the down-selection to 3 or 4 M-class missions, which will proceed to the definition phase. The main goal of this internal review was to identify the mission's critical issues and associated risks at technical, programmatic and financial level. |
| Publication date: 12 Nov 2009 |
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| Final Report of the 2016 Mars Orbiter Bus Joint Instrument Definition Team |
| This report was compiled by the Joint Instrument Definition Team for the 2016 Mar Orbiter Bus.
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| Publication date: 10 Nov 2009 |
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| PLATO Mission Assessment Study - Executive Summary (Thales Alenia Space) |
| The PLATO Mission Assessment Study is the industrial part of the PLATO assessment phase. Two parallel 1-year assessment studies have been concluded. This report is the executive summary for the study led by Thales Alenia Space Italia (responsible of the system definition and the platform design) with Thales Alenia Space France (responsible of the payload). |
| Publication date: 09 Nov 2009 |
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| XMMSL1 J060636.2-694933: an XMM-Newton slew discovery and Swift/Magellan follow up of a new classical nova in the LMC |
Aims. In order to discover new X-ray transients, the data taken by XMM-Newton as it slews between targets are being processed and cross-correlated with other X-ray observations.
Methods. A bright source, XMMSL1 J060636.2-694933, was detected on 18 July 2006 at a position where no previous X-ray source had been seen. The XMM-Newton slew data, plus follow-up dedicated XMM-Newton and Swift observations, plus optical data acquired with the Magellan Clay telescope, and archival All-Sky Automated Survey (ASAS) data were used to classify the new object, and to investigate its properties.
Results. No XMM-Newton slew X-ray counts are detected above 1 keV and the source is seen to be over five hundred times brighter than the ROSAT All-Sky Survey upper limit at that position. The line-rich optical spectrum acquired with the Magellan telescope allows the object to be classified as an A0 auroral phase nova, and the soft X-ray spectrum indicates that the nova was in a super-soft source state in the X-ray decline seen in the follow-up X-ray observations. The archival ASAS data suggests that the nova at onset (Oct 2005) was a "very fast" nova, and an estimate of its distance is consistent with the nova being situated within the LMC.
Conclusions. With the discovery presented here of a new classical nova in the LMC, it is clear that XMM-Newton slew data are continuing to offer a powerful opportunity to find new X-ray transient objects. |
| Publication date: 08 Nov 2009 |
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| Evidence of a long-term trend in total solar irradiance |
| During the solar minimum of 2008, the value of total solar irradiance at 1 AU (TSI) was more than 0.2 Wm/2 lower than during the last minimum in 1996, indicating for the first time a directly observed long-term change. In contrast, chromospheric indices and hence solar UV irradiance do not exhibit a similar change.
Comparison of TSI with other activity parameters indicates that only the open solar magnetic field, BR, observed from satellites at 1 AU show a similar long-term behaviour. The values at the minima correlate well and the linear fit provides a direct physical relationship between TSI and BR during the minimum times. This correlation allows an unambiguous reconstruction of TSI back in time, provided the open solar magnetic field can be determined from e.g. geomagnetic indices or cosmogenic radionucleides. Since the solar UV irradiance has no long-term trend, the mechanism for the secular change of TSI must differ from the effect of surface magnetism, as manifested by sunspots, faculae, and network which indeed explain well the intra-cycle variability of both total and spectral irradiance. The long-term trend of TSI is most probably caused by a global temperature change of the Sun that does not influence the UV irradiance in the same way as the surface magnetic fields. |
| Publication date: 05 Nov 2009 |
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| Pre-flight calibration of LYRA, the solar VUV radiometer on board PROBA2 |
Aims. LYRA, the Large Yield Radiometer, is a vacuum ultraviolet (VUV) solar radiometer, planned to be launched in November 2009 on the European Space Agency PROBA2, the Project for On-Board Autonomy spacecraft.
Methods. The instrument was radiometrically calibrated in the radiometry laboratory of the Physikalisch-Technische Bundesanstalt (PTB) at the Berlin Electron Storage ring for SYnchroton radiation (BESSY II). The calibration was done using monochromatized
synchrotron radiation at PTBs VUV and soft X-ray radiometry beamlines using reference detectors calibrated with the help of an
electrical substitution radiometer as the primary detector standard.
Results. A total relative uncertainty of the radiometric calibration of the LYRA instrument between 1% and 11% was achieved. LYRA
will provide irradiance data of the Sun in four UV passbands and with high temporal resolution down to 10 ms. The present state of
the LYRA pre-flight calibration is presented as well as the expected instrument performance. |
| Publication date: 04 Nov 2009 |
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| A new topographical image atlas of Phobos |
| Phobos flyby images obtained by the High Resolution Stereo Camera (HRSC) and the Super Resolution Channel (SRC) onboard the Mars Express spacecraft were used to produce a global Digital Terrain Model and orthoimage mosaics. We derived a set of Phobos topographic image maps, which are combined into an atlas that consists of four quadrangles on three map sheets at the scale of 1: 50,000. The lateral geometric accuracy of these maps of ± 20 m is more than four times better than that of past products. They are based on a shape model with 0.52° × 0.52° grid spacing and show significantly more detail in comparison to previous data products. |
| Publication date: 02 Nov 2009 |
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| Marco Polo Assessment Study - Executive Summary Report |
Executive Summary of the mission study by EADS Astrium (Reference: MP.ASU.ES). The Marco Polo Assessment Study under ESA contract led by Astrium Ltd has focused on an ESA-defined scenario, defining a feasible mission architecture for the mission and providing preliminary designs for the spacecraft and Earth Re-entry Capsule. Trade-offs have been carried out to determine the optimum launch and transfer strategy, proximity operations, and return strategy. In parallel the key-technologies for the mission have been assessed and the development requirements identified. |
| Publication date: 02 Nov 2009 |
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