Author
P. Fougeray
Bio: P. Fougeray is an academic researcher from State University of New York System. The author has contributed to research in topics: Cosmic dust & Interstellar medium. The author has an hindex of 2, co-authored 4 publications receiving 33 citations.
Papers
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University of California, Berkeley1, Goethe University Frankfurt2, European Synchrotron Radiation Facility3, École normale supérieure de Lyon4, Ghent University5, Field Museum of Natural History6, United States Naval Research Laboratory7, Lawrence Berkeley National Laboratory8, University of Leicester9, University of Washington10, University of Kent11, University of New Mexico12, University of Chicago13, Washington University in St. Louis14, State University of New York at Plattsburgh15, Max Planck Society16, Ames Research Center17, Natural History Museum18, Argonne National Laboratory19, Carnegie Institution for Science20, Heidelberg University21, University of Stuttgart22, Braunschweig University of Technology23, Jet Propulsion Laboratory24, Osaka University25
TL;DR: Using synchrotron-based X-ray diffraction measurements, the authors identified crystalline material in two particles of extraterrestrial origin extracted from the Stardust Interstellar Dust Collector.
Abstract: Using synchrotron-based X-ray diffraction measurements, we identified crystalline material in two particles of extraterrestrial origin extracted from the Stardust Interstellar Dust Collector. The first particle, I1047,1,34 (Hylabrook), consisted of a mosaiced olivine grain approximately 1 mu m in size with internal strain fields up to 0.3%. The unit cell dimensions were a - 4.85 +/- 0.08 angstrom, b - 10.34 +/- 0.16 angstrom, c - 6.08 +/- 0.13 angstrom (2 sigma). The second particle, I1043,1,30 (Orion), contained an olivine grain approximate to 2 mu m in length and > 500 nm in width. It was polycrystalline with both mosaiced domains varying over approximate to 20 degrees and additional unoriented domains, and contained internal strain fields < 1%. The unit cell dimensions of the olivine were a = 4.76 +/- 0.05 angstrom, b = 10.23 +/- 0.10 angstrom, c = 5.99 +/- 0.06 angstrom (2 sigma), which limited the olivine to a forsteritic composition [Fo(65) (2 sigma). Orion also contained abundant spinel nanocrystals of unknown composition, but unit cell dimension a = 8.06 +/- 0.08 angstrom (2 sigma). Two additional crystalline phases were present and remained unidentified. An amorphous component appeared to be present in both these particles based on STXM and XRF results reported elsewhere.
18 citations
Goethe University Frankfurt1, University of California, Berkeley2, Ghent University3, European Synchrotron Radiation Facility4, Field Museum of Natural History5, United States Naval Research Laboratory6, Lawrence Berkeley National Laboratory7, University of Leicester8, University of Washington9, University of Kent10, George Washington University11, University of Chicago12, Washington University in St. Louis13, State University of New York at Plattsburgh14, Max Planck Society15, Natural History Museum16, Argonne National Laboratory17, École normale supérieure de Lyon18, Carnegie Institution for Science19, University of Hawaii at Manoa20, Ames Research Center21, University of Stuttgart22, Jet Propulsion Laboratory23, Planetary Science Institute24
TL;DR: In this article, the elemental composition of eight candidate impact features extracted from the Stardust Interstellar Dust Collector (SIDC) was analyzed by synchrotron X-ray fluorescence microscopy.
Abstract: Here, we report analyses by synchrotron X-ray fluorescence microscopy of the elemental composition of eight candidate impact features extracted from the Stardust Interstellar Dust Collector (SIDC). Six of the features were unambiguous tracks, and two were crater-like features. Five of the tracks are so-called “midnight” tracks—that is, they had trajectories consistent with an origin either in the interstellar dust stream or as secondaries from impacts on the Sample Return Capsule (SRC). In a companion paper reporting synchrotron X-ray diffraction analyses of ISPE candidates, we show that two of these particles contain natural crystalline materials: the terminal particle of track 30 contains olivine and spinel, and the terminal particle of track 34 contains olivine. Here, we show that the terminal particle of track 30, Orion, shows elemental abundances, normalized to Fe, that are close to CI values, and a complex, fine-grained structure. The terminal particle of track 34, Hylabrook, shows abundances that deviate strongly from CI, but shows little fine structure and is nearly homogenous. The terminal particles of other midnight tracks, 29 and 37, had heavy element abundances below detection threshold. A third, track 28, showed a composition inconsistent with an extraterrestrial origin, but also inconsistent with known spacecraft materials. A sixth track, with a trajectory consistent with secondary ejecta from an impact on one of the spacecraft solar panels, contains abundant Ce and Zn. This is consistent with the known composition of the glass covering the solar panel. Neither crater-like feature is likely to be associated with extraterrestrial materials. We also analyzed blank aerogel samples to characterize background and variability between aerogel tiles. We found significant differences in contamination levels and compositions, emphasizing the need for local background subtraction for accurate quantification.
13 citations
University of California, Berkeley1, University of Grenoble2, Goethe University Frankfurt3, European Synchrotron Radiation Facility4, École Normale Supérieure5, Ghent University6, University of Chicago7, United States Naval Research Laboratory8, Lawrence Berkeley National Laboratory9, University of Leicester10, University of Washington11, Ames Research Center12, Max Planck Society13
TL;DR: In this article, the authors analyzed two of these via nanodiffraction at the European Synchrotron Radiation Facility (ESRF) and found them to contain crystalline components and identified the most likely mineral components as olivine and spinel.
Abstract: NASA's interstellar collector from the Stardust mission captured several particles that are now thought to be of interstellar origin We analyzed two of these via nanodiffraction at the European Synchrotron Radiation Facility (ESRF) and found them to contain crystalline components The unit cell of the crystalline material is determined from the diffraction patterns and the most likely mineral components are identified as olivine and spinel
2 citations
01 Jan 2011
TL;DR: In 2006, the Stardust sample return capsule returned to Earth bearing the first solid samples from a primitive solar system body, Comet 81P/Wild2, and a collector dedicated to the capture and return of contemporary interstellar dust.
Abstract: In January 2006, the Stardust sample return capsule returned to Earth bearing the first solid samples from a primitive solar system body, Comet 81P/Wild2, and a collector dedicated to the capture and return of contemporary interstellar dust Both collectors were approx 01 sq m in area and were composed of aerogel tiles (85% of the collecting area) and aluminum foils The Stardust Interstellar Dust Collector (SIDC) was exposed to the interstellar dust stream for a total exposure factor of 20 sq m/day The Stardust Interstellar Preliminary Examination (ISPE) is a consortium-based project to characterize the collection using nondestructive techniques The goals and restrictions of the ISPE are described A summary of analytical techniques is described
2 citations
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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
Space Sciences Laboratory1, Lawrence Berkeley National Laboratory2, Goethe University Frankfurt3, State University of New York at Plattsburgh4, Heidelberg University5, Braunschweig University of Technology6, University of Stuttgart7, Empik8, United States Naval Research Laboratory9, Field Museum of Natural History10, University of Leicester11, University of Washington12, University of Kent13, European Synchrotron Radiation Facility14, George Washington University15, University of Chicago16, Washington University in St. Louis17, Max Planck Society18, Natural History Museum19, Argonne National Laboratory20, École normale supérieure de Lyon21, university of lille22, Carnegie Institution for Science23, Ames Research Center24, Ghent University25, Jet Propulsion Laboratory26, Osaka University27
TL;DR: The results from the preliminary examination of this collection, the Stardust Interstellar Preliminary Examination (ISPE), were presented in this article, where extraterrestrial materials were found in two tracks in aerogel whose trajectories and morphology are consistent with an origin in the interstellar dust stream, and in residues in four impacts in the aluminum foil collectors.
Abstract: With the discovery of bona fide extraterrestrial materials in the Stardust Interstellar Dust Collector, NASA now has a fundamentally new returned sample collection, after the Apollo, Antarctic meteorite, Cosmic Dust, Genesis, Stardust Cometary, Hayabusa, and Exposed Space Hardware samples. Here, and in companion papers in this volume, we present the results from the Preliminary Examination of this collection, the Stardust Interstellar Preliminary Examination (ISPE). We found extraterrestrial materials in two tracks in aerogel whose trajectories and morphology are consistent with an origin in the interstellar dust stream, and in residues in four impacts in the aluminum foil collectors. While the preponderance of evidence, described in detail in companion papers in this volume, points toward an interstellar origin for some of these particles, alternative origins have not yet been eliminated, and definitive tests through isotopic analyses were not allowed under the terms of the ISPE. In this summary, we answer the central questions of the ISPE: How many tracks in the collector are consistent in their morphology and trajectory with interstellar particles? How many of these potential tracks are consistent with real interstellar particles, based on chemical analysis? Conversely, what fraction of candidates are consistent with either a secondary or interplanetary origin? What is the mass distribution of these particles, and what is their state? Are they particulate or diffuse? Is there any crystalline material? How many detectable impact craters (> 100 nm) are there in the foils, and what is their size distribution? How many of these craters have analyzable residue that is consistent with extraterrestrial material? And finally, can craters from secondaries be recognized through crater morphology (e.g., ellipticity)?
35 citations
TL;DR: In this paper, the origin of the secondary impacts can be determined by either analysis of the residue in the craters in the foils, which preserve an elemental signature of the solar cell components, or by their pointing direction for tracks in the aerogel.
Abstract: – We have shown in laboratory experiment that hypervelocity impacts on a solar cell produce ejecta that can be captured on aluminum (Al 1100) foil or in low density (33 kg m−3) aerogel. The origin of the secondary impacts can be determined by either analysis of the residue in the craters in the foils (which preserve an elemental signature of the solar cell components) or by their pointing direction for tracks in the aerogel (which we show align with the impact direction to ± 0.4°). This experimental evidence explains the observations of the NASA Stardust mission which has reported that the majority of tracks in the aerogel collector used to collect interstellar dust actually point at the spacecraft’s solar panels. From our results, we suggest that it should also be possible to recognize secondary ejecta craters in the Stardust mission aluminum foils, also used as dust sampling devices during the mission.
27 citations
01 Jan 1994
26 citations
Space Sciences Laboratory1, Lawrence Berkeley National Laboratory2, Field Museum of Natural History3, United States Naval Research Laboratory4, Goethe University Frankfurt5, University of Leicester6, University of Washington7, University of Kent8, European Synchrotron Radiation Facility9, George Washington University10, University of Chicago11, State University of New York at Plattsburgh12, Max Planck Society13, Heidelberg University14, Natural History Museum15, Argonne National Laboratory16, École normale supérieure de Lyon17, university of lille18, Carnegie Institution for Science19, Ames Research Center20, Ghent University21, University of Stuttgart22, Braunschweig University of Technology23, Jet Propulsion Laboratory24, Osaka University25
TL;DR: In this paper, the authors report the quantitative characterization by synchrotron soft X-ray spectroscopy of 31 potential impact features in the aerogel capture medium of the Stardust Interstellar Dust Collector.
Abstract: We report the quantitative characterization by synchrotron soft X-ray spectroscopy of 31 potential impact features in the aerogel capture medium of the Stardust Interstellar Dust Collector. Samples were analyzed in aerogel by acquiring high spatial resolution maps and high energy-resolution spectra of major rock-forming elements Mg, Al, Si, Fe, and others. We developed diagnostic screening tests to reject spacecraft secondary ejecta and terrestrial contaminants from further consideration as interstellar dust candidates. The results support an extraterrestrial origin for three interstellar candidates: I1043,1,30 (Orion) is a 3 pg particle with Mg-spinel, forsterite, and an iron-bearing phase. I1047,1,34 (Hylabrook) is a 4 pg particle comprising an olivine core surrounded by low-density, amorphous Mg-silicate and amorphous Fe, Cr, and Mn phases. I1003,1,40 (Sorok) has the track morphology of a high-speed impact, but contains no detectable residue that is convincingly distinguishable from the background aerogel. Twenty-two samples with an anthropogenic origin were rejected, including four secondary ejecta from impacts on the Stardust spacecraft aft solar panels, nine ejecta from secondary impacts on the Stardust Sample Return Capsule, and nine contaminants lacking evidence of an impact. Other samples in the collection included I1029,1,6, which contained surviving solar system impactor material. Four samples remained ambiguous: I1006,2,18, I1044,2,32, and I1092,2,38 were too dense for analysis, and we did not detect an intact projectile in I1044,3,33. We detected no radiation effects from the synchrotron soft X-ray analyses; however, we recorded the effects of synchrotron hard X-ray radiation on I1043,1,30 and I1047,1,34.
19 citations