J. Leitner
A5046221607- Astro and Planetary Science
- Planetary Science and Exploration
- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Isotope Analysis in Ecology
- Gamma-ray bursts and supernovae
- Spacecraft and Cryogenic Technologies
- Nuclear Physics and Applications
- Laser-induced spectroscopy and plasma
- High-pressure geophysics and materials
- Geology and Paleoclimatology Research
- Ion-surface interactions and analysis
- Atmospheric Ozone and Climate
- Geomagnetism and Paleomagnetism Studies
- Geological and Geochemical Analysis
- Space Exploration and Technology
- Integrated Circuits and Semiconductor Failure Analysis
- Marine and environmental studies
- High-Velocity Impact and Material Behavior
- Astronomy and Astrophysical Research
- Silicon Effects in Agriculture
- X-ray Spectroscopy and Fluorescence Analysis
- Space Satellite Systems and Control
- Space Science and Extraterrestrial Life
- Paleontology and Stratigraphy of Fossils
Max Planck Institute for Chemistry
2016-2025
Heidelberg University
2023-2025
Max Planck Society
2011-2021
Max Planck Innovation
2011-2014
Max Planck Institute for Nuclear Physics
2014
University of Münster
2003-2008
Ames Research Center
2006
Lawrence Livermore National Laboratory
2006
Johnson Space Center
2006
Centre de Recherches Pétrographiques et Géochimiques
2006
The Stardust spacecraft collected thousands of particles from comet 81P/Wild 2 and returned them to Earth for laboratory study. preliminary examination these samples shows that the nonvolatile portion is an unequilibrated assortment materials have both presolar solar system origin. contains abundance silicate grains are much larger than predictions interstellar grain models, many high-temperature minerals appear formed in inner regions nebula. Their presence a proves formation included...
Organics found in comet 81P/Wild 2 samples show a heterogeneous and unequilibrated distribution abundance composition. Some organics are similar, but not identical, to those interplanetary dust particles carbonaceous meteorites. A class of aromatic-poor organic material is also present. The rich oxygen nitrogen compared with meteoritic organics. Aromatic compounds present, the tend be relatively poorer aromatics than meteorites particles. presence deuterium nitrogen-15 excesses suggest that...
Particles emanating from comet 81P/Wild 2 collided with the Stardust spacecraft at 6.1 kilometers per second, producing hypervelocity impact features on collector surfaces that were returned to Earth. The morphologies of these surprisingly diverse created by particles varying dense mineral grains loosely bound, polymineralic aggregates ranging tens nanometers hundreds micrometers in size. cumulative size distribution Wild dust is shallower than Halley, yet steeper Grigg-Skjellerup.
We measured the elemental compositions of material from 23 particles in aerogel and residue seven craters aluminum foil that was collected during passage Stardust spacecraft through coma comet 81P/Wild 2. These are chemically heterogeneous at largest size scale analyzed (â¼180 ng). The mean composition this Wild 2 is consistent with CI meteorite composition, which thought to represent bulk solar system, for elements Mg, Si, Mn, Fe, Ni 35%, Ca Ti 60%. Cu, Zn, Ga appear enriched material,...
Seven particles captured by the Stardust Interstellar Dust Collector and returned to Earth for laboratory analysis have features consistent with an origin in contemporary interstellar dust stream. More than 50 spacecraft debris were also identified. The candidates are readily distinguished from impacts on basis of elemental composition and/or impact trajectory. seven candidate diverse composition, crystal structure, size. presence crystalline grains multiple iron-bearing phases, including...
We have studied more than 2000 presolar silicon carbide (SiC) grains from the Murchison CM2 chondrite in size range 0.2–0.5 μm for C- and Si-isotopic compositions. In a subset of these grains, we also measured N-, Mg–Al-, S-, Ca–Ti-isotopic compositions as well trace element concentrations. The overall picture emerging isotope data is quite comparable with that larger except abundances Type II supernovae (SNeII) low-metallicity asymptotic giant branch (AGB) stars. Especially, latter are much...
We investigated the inventory of presolar silicate, oxide, and silicon carbide (SiC) grains in CR2 chondrite Northwest Africa (NWA) 852. Thirty-one O-anomalous were detected: 24 identified as silicates (∼78 ppm); remaining 7 are Al-rich oxides (∼38 ppm). NWA 852 is first C2 containing dust concentrations comparable to other more primitive meteorites. Eight SiC have been found, representing highest abundance (∼160 ppm) observed so far 15N-enriched matter also present, although very...
Abstract— Aluminum foils of the Stardust cometary dust collector are peppered with impact features a wide range sizes and shapes. By comparison to laboratory shots known particle dimensions density, using same velocity incidence geometry as Wild 2 encounter, we can derive size mass grains. Using scanning electron microscopy (SEM) foil samples (both flown on mission impacted in laboratory) have recognized feature shapes from which interpret density internal structure. We documented...
Abstract— In January 2006, the Stardust mission successfully returned dust samples from tail of comet 81P/Wild 2 in two principal collection media, low‐density silica aerogel and Al foil. While hypervelocity impacts at encounter velocity 6.1 km/s into foils are generally highly disruptive for natural, silicate‐dominated impactors, previous studies have shown that many craters retain sufficient residue to allow a determination elemental isotopic compositions original projectile. We used...
Abstract With the discovery of bona fide extraterrestrial materials in Stardust Interstellar Dust Collector, NASA now has a fundamentally new returned sample collection, after Apollo, Antarctic meteorite, Cosmic Dust, Genesis, Cometary, Hayabusa, and Exposed Space Hardware samples. Here, companion papers this volume, we present results from Preliminary Examination ( ISPE ). We found two tracks aerogel whose trajectories morphology are consistent with an origin interstellar dust stream,...
Significance Organic matter from the parent molecular cloud of our solar system can be located in primitive extraterrestrial samples like meteorites and cometary grains. This pristine contains among most organic molecules that were delivered to early Earth 4.5 billion years ago. We have analyzed these organics by a high-resolution electron microscope is exceptionally suited study beam-sensitive materials. Different carbon nitrogen functional groups identified on submicron scale attributed...
We studied about 5000 μm2 of fine-grained matrix material in the Acfer 094 meteorite by high-resolution (nominal 50 nm) NanoSIMS ion imaging for presence O-rich presolar (stardust) grains. This approach permits identifying grains down to <100 nm size, compared >150 lower-resolution 100 surveys. The number density identified is a factor two three higher than what was found studies. abundances O isotope Group 3 and 4 are previously found. None shows strong enrichments 16O expected from model...
Abstract On the basis of an interstellar dust model compatible with Ulysses and Galileo observations, we calculate predict trajectories ( ISD ) in solar system distribution impact speeds, directions, flux particles on Stardust Interstellar Dust Collector during two collection periods mission. We find that expected velocities are generally low (<10 km s −1 for ratio radiation pressure force to gravitational β > 1, some will cometary side collector. If assume astronomical silicates...
Abstract We report on Mg and Si isotope data of 86 presolar silicate grains identified through NanoSIMS oxygen ion imaging in thin sections carbonaceous ordinary chondrites. The O, Mg, 106 silicates (including studied previously by our group) suggest division O Group 1 into four subpopulations: (i) “normal,” (ii) 25 Mg-rich, (iii) 26 (iv) Mg-poor. Normal (∼60% grains) formed the winds low-mass asymptotic giant branch (AGB) stars, with defining linear arrays slopes ∼0.9 1.37, respectively,...
Abstract Organic matter in extraterrestrial samples is a complex material that might have played an important role the delivery of prebiotic molecules to early Earth. We report here on identification nitrogen-containing compounds such as amino acids and N-heterocycles within recent observed meteorite fall Winchcombe by high-spatial resolution spectroscopy techniques. Although nitrogen contents organic are low (N/C ~ 1–3%), we were able detect presence these using low-noise direct electron...
Abstract Here, we report the identification of 69 tracks in approximately 250 cm 2 aerogel collectors Stardust Interstellar Dust Collector. We identified these through Stardust@home, a distributed internet‐based virtual microscope and search engine, which > 30,000 amateur scientists collectively performed >9 × 10 7 searches on 6 fields view. Using calibration images, measured individual detection efficiency, found that efficiency for 2.5 μm diameter was >0.6, >0.75 >3...
Abstract We investigated the inventory of presolar silicate, oxide, and silicon carbide (SiC) grains fine‐grained chondrule rims in six Mighei‐type ( CM ) carbonaceous chondrites (Banten, Jbilet Winselwan, Maribo, Murchison, Murray Yamato 791198), ‐related chondrite Sutter's Mill. Sixteen O‐anomalous (nine silicates, oxides) were detected, corresponding to a combined matrix‐normalized abundance ~18 ppm, together with 21 SiC (~42 ppm). Twelve O‐rich are enriched 17 O, could originate from...