Global ETD Search
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Showing 1 to 20 of 20 for “"solar nebula"”.
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Paleomagnetic Investigation of Enstatite Chondrite Chondrules: Implications for the Solar Nebula
The early stages of solar system formation were characterized by the rapid evolution of the protoplanetary disk. A magnetic field governed the highly efficient mass and angular momentum transport systems. Paleomagnetic measurements of chondrites have constrained the intensity of the nebular field …
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The crystal chemistry of hibonite: an indicator for oxygen fugacity during Solar nebula condensation?
… can give information on the early history of our Solar System. In particular, Calcium-Aluminium-rich inclusions (CAIs), which are usually found in carbonaceous chondrites, yielded the oldest measured ages of our Solar System. CAIs can contain records of the conditions and the events that …
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A TEM study of crystalline silicates in the matrices of MET 00426 and QUE 99177 CR3.0 chondrites: Constraints on the formation mechanisms of dust in the solar nebula
Understanding the constituents of fine-grained nebular dust prior to asteroidal accretion is a significant challenge in meteoritics. The key to understanding nebular dust lies in chondritic meteorites, which are composed of undifferentiated solar system materials. Chondritic matrices are a …
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Constraining Planetary Science Problems with Micro-Paleomagnetism
… and (2) how did the magnetic field in the solar nebula varied in space and time. For the first, I conducted paleomagnetic measurements with the Jack Hills zircon grains from Western Australia to address the early evolution of Earth’s magnetic field, which has implications for the thermal …
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Constraints on the surface composition of Trojan asteroidsfrom near infrared (0.8-4.0 μm) spectroscopy and spectral modeling
… to understanding the conditions under which the solar system formed. Characterization of the inner solar nebula progresses rapidly due to remote studies of asteroid and planetary surfaces as well as laboratory analyses of meteorites and lunar samples. Because of their atypical orbital position at …
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The chlorine isotope composition of chondrites : evidence for a single nebular reservoir and the effects of secondary processes on chondrite parent bodies
… isotopic reservoirs that were present in the solar nebula and the effect of secondary processes on the isotopic composition. We analyzed twenty chondrites that included both unaltered (type 3) and altered (types 1-2, 4-6) chondrites from the carbonaceous, ordinary, and enstatite classes. …
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Mineralogy and bulk chemistry of chondrules and matrix in petrologic type 3 chondrites : implications for early solar system processes
… of the most pristine material that formed in the solar nebula. Chondrule characteristics and the complementary relationship between the compositions of chondrules and matrix suggest open system behavior during chondrule formation, in the form of evaporation and recondensation of volatile and …
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Decoding the history of the early solar system using comet volatile compositions
<p>"Understanding the evolution of the solar system, as well as its current volatile content, requires knowledge of the initial conditions present in the solar nebula. As some of the first objects to accrete in the solar nebula, cometary nuclei are among the most primitive remnants of solar system …
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Magnetic fields in the early solar system
The first magnetic fields in the solar system were embedded in the ionized gas of the protoplanetary disk itself. Soon after, newly formed protoplanets may have harbored magnetic core dynamos. Paleomagnetic analysis of ancient samples permits direct constraints on these early solar system magnetic …
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MICROSTRUCTURAL CONSTRAINTS ON THE FORMATIONAL AND THERMAL HISTORIES OF REFRACTORY INCLUSIONS IN CO3 CHONDRITES
… and subsequent thermal histories both in the solar nebula and on their asteroidal parent bodies. In particular, refractory inclusions in CO3 chondrites are very fine-grained so that they are sensitive recorders of both primary formational and secondary alteration processes, which can only be …
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The role of vortices in the formation of the solar system
… enhance the coagulation of dust particles in the solar nebula. An inviscid, barotropic, two-dimensional form of the vorticity equation is derived to study the gas flow. A pseudospectral numerical model uses this equation to calculate the evolution of the vorticity field. The calculations show that …
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Iron Isotope Cosmochemistry
… tracers used to understand the origin of the Solar System, planetary formation, and differentiation processes such as the moon-forming giant impact, core-mantle segregation, and crust formation. In this dissertation, I report the most complete dataset of high-precision iron isotope …
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Deuterium Enrichment and the Kinetic Isotope Effect during Ruthenium Catalyzed Fischer-Tropsch Synthesis
… and the formation of organic matter in the solar nebula. Analysis of this synthesis was carried out with a ruthenium catalyst at controlled temperatures and pressures. Two types of experiments were performed: H2/D2 switching and competitive methods. The products showed that the hydrocarbon …
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Stochastic histories of dust grains in the interstellar medium
… may have been present within the primordial solar nebula. (2) structured or layered refractory dust grains within our model cannot explain the observed interstellar depletions of refractory material. (3) fragmentation due to grain-grain collisions in the diffuse phase plus the accretion of …
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Formation conditions of plagioclase-bearing type I chondrules in CO chondrites : a study of natural samples and experimental analogs
… that contain components that formed in the early solar system. One of the components found in chondrites is chondrules, which are small igneous spherules that formed from the melting of precursor dust ball assemblages during very short, high-temperature events in the solar nebula. Chondrules …
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Physical and Chemical Properties of Matrix in Primitive Chondrites
The origin and formation of our Solar System is an open research question, which the scientific community is trying to address. In this work was specifically investigated the fine grained matrix which is a mixture of fine-grained materials composed largely of amorphous silicate and sub-micrometre …
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Thermal histories of CB meteorites: Constraints from compositions and microstructures of sulfides
… 2005; Krot et al., 2005], rather than in the solar nebula. This study focuses on textures and compositions of homogeneous and exsolved sulfides in metal grains in CB meteorites to constrain secondary thermal histories. We use SEM, EPMA, FIB, and TEM techniques to examine metal and sulfides, …
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Spectral Study of Asteroids and Laboratory Simulation of Asteroid Organics
… irradiation and/or formation region in the solar nebula.
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XCT, SEM, and LA-ICP-MS map investigation of chondrule FGRS in CM2 Aguas Zarcas
… enabling a novel investigation into early solar system processes, providing insights into FGR formation and trace element patterns across FGR and matrix to investigate their genetic relationships and alteration history. We performed shape and volume analyses of chondrule cores and FGRs …