Diffusion kinetics of Cr in olivine and 53Mn–53Cr thermochronology of early solar system objects

2006 ◽  
Vol 70 (3) ◽  
pp. 799-809 ◽  
Author(s):  
Motoo Ito ◽  
Jibamitra Ganguly
Keyword(s):  
Solar System ◽  
Diffusion Kinetics ◽  
Early Solar System ◽  
Solar System Objects ◽  
Kinetics Of

scholarly journals 6. Condensation and/or Metamorphism: Genesis of E- and L-Group Chondrites from Studies on Artificially Heated Primitive Congeners

1977 ◽  
Vol 39 ◽  
pp. 375-383
Author(s):  
M. E. Lipschutz ◽  
M. Ikramuddin
Keyword(s):  
Trace Elements ◽  
Solar System ◽  
Compositional Data ◽  
Condensation Process ◽  
Early Solar System ◽  
Volatile Element ◽  
Solar System Objects ◽  
Trace Element Contents ◽  
Element Contents ◽  
Apparent Activation Energies

Primitive chondrites heated for one week under conditions reasonable for early solar system objects readily lose volatile/mobile trace elements, e.g., Ag, Bi, Cs, Ga, In, Se, Te, Tl and Zn. Trace element contents decrease by 10-100x progressively with temperature up to 1000° C; apparent activation energies calculated from these data suggest bonding differences between chondrites. Comparison of data for E3-6 chondrites and heated Abee (E4) indicates that volatile/mobile trace elements in E-group chondrites reflect metamorphic loss from a parent object; prior nebular cosmochemical fractionation modified non-volatile element contents. Apparently L3-6 chondrites escaped such open-system metamorphism. Information on nebular condensation process(es) may be gained from L-group compositional data; only nonvolatile elements in E-group chondrites should be used for this purpose, however.

Laboratory and in-situ analysis of comet dust

1988 ◽  
Vol 46 ◽  
pp. 8-9
Author(s):  
D.E. Brownlee ◽  
A.L. Albee
Keyword(s):  
Electron Microscopy ◽  
Solar System ◽  
Laboratory Study ◽  
Isotopic Analysis ◽  
Building Blocks ◽  
Sem Analysis ◽  
Early Solar System ◽  
Cometary Material ◽  
Comet Dust

Comets are primitive, kilometer-sized bodies that formed in the outer regions of the solar system. Composed of ice and dust, comets are generally believed to be relic building blocks of the outer solar system that have been preserved at cryogenic temperatures since the formation of the Sun and planets. The analysis of cometary material is particularly important because the properties of cometary material provide direct information on the processes and environments that formed and influenced solid matter both in the early solar system and in the interstellar environments that preceded it.The first direct analyses of proven comet dust were made during the Soviet and European spacecraft encounters with Comet Halley in 1986. These missions carried time-of-flight mass spectrometers that measured mass spectra of individual micron and smaller particles. The Halley measurements were semi-quantitative but they showed that comet dust is a complex fine-grained mixture of silicates and organic material. A full understanding of comet dust will require detailed morphological, mineralogical, elemental and isotopic analysis at the finest possible scale. Electron microscopy and related microbeam techniques will play key roles in the analysis. The present and future of electron microscopy of comet samples involves laboratory study of micrometeorites collected in the stratosphere, in-situ SEM analysis of particles collected at a comet and laboratory study of samples collected from a comet and returned to the Earth for detailed study.

Preface: Evolution of the early solar system: Presolar cosmochemical fingerprints and the formation of watery rocky planets

2016 ◽  
Vol 50 (1) ◽  
pp. 1-2 ◽  
Author(s):  
Tomohiro Usui ◽  
Audrey Bouvier ◽  
Justin I. Simon ◽  
Noriko Kita
Keyword(s):  
Solar System ◽  
Early Solar System ◽  
Rocky Planets

Kinetics of Methane-Oxidizing Biofilms for Degradation of Toxic Organics

1988 ◽  
Vol 20 (11-12) ◽  
pp. 167-173 ◽  
Author(s):  
S. E. Strand ◽  
R. M. Seamons ◽  
M. D. Bjelland ◽  
H. D. Stensel
Keyword(s):  
Chlorinated Hydrocarbons ◽  
Enzymatic Oxidation ◽  
Diffusion Kinetics ◽  
Toxic Compound ◽  
Biofilm Model ◽  
Uptake Rates ◽  
Substrate Diffusion ◽  
Toxic Organics ◽  
Competitive Substrate ◽  
Kinetics Of

The kinetics of methane-oxidizing bioreactors for the degradation of toxic organics are modeled. Calculations of the fluxes of methane and toxic chlorinated hydrocarbons were made using a biofilm model. The model simulated the effects of competition by toxics and mediane on their enzymatic oxidation by the methane monooxygenase. Dual-competitive-substrate/diffusion kinetics were used to model biofilm co-metabolism, integrating equations of the following form:where S1 and S2 are the local concentrations of methane and toxic compound, respectively, and r and K are the maximum uptake rates and Monod coefficients, and x is the distance into the biofilm.

A nearby neutron-star merger explains the actinide abundances in the early Solar System

Nature ◽  
2019 ◽  
Vol 569 (7754) ◽  
pp. 85-88 ◽  
Author(s):  
Imre Bartos ◽  
Szabolcs Marka
Keyword(s):  
Neutron Star ◽  
Solar System ◽  
Early Solar System
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