Meteorites and the early solar system II , edited by Dante S. Lauretta and Harry Y. McSween, Jr (original) (raw)
Related papers
Primitive meteorites contain clues on the astrophysical environment in which the solar system formed. The processing of chemical and isotopic signatures in the protoplanetary disk were preserved in the components of undifferentiated meteorites known as chondrites. The meteoritical evidence inherent to these primordial materials strongly supports that the solar system formed in a stellar association, probably under the presence of some intermediate or even massive star. Chondritic minerals also contain the fingerprints of stellar nucleosynthesis. Short-lived nuclides and stellar synthesized grains from nearby stars were incorporated into the solar nebula before the condensation of the first minerals from the hot vapor phase. Therefore, the isotopic ratios preserved in chondrites provide clues on the stellar sources that produced these nuclides, being supernovae and Asymptotic Giant Branch stars two likely contributors. A recent model has concluded that the inferred SLNs initial ratios in chondrites seems to be consistent with a 6.5 solar masses AGB star. To answer this question additional clues need to be obtained from the study of stellar grains and organic components preserved in pristine chondrites, Interplanetary Dust Particles, and future sample-returned materials from primitive asteroids and comets.
Meteorites from the outer solar system
2008
We investigate the possibility that a small fraction of meteorites originate from the outer solar system, ie, from the Kuiper belt, the Oort cloud, or from the Jupiter-family comet reservoir. Dynamical studies and meteor observations show that it is possible for cometary solid fragments to reach Earth with a velocity not unlike that of asteroidal meteorites. Cosmochemical data and orbital studies identify CI1 chondrites as the best candidates for being cometary meteorites.
Meteorites: Messengers from the Early Solar System
CHIMIA International Journal for Chemistry, 2010
Meteorites are fragments from solar system bodies, dominantly asteroids. A small fraction is derived from the Moon and from Mars. These rocks tell a rich history of the early solar system and range from solids little changed since the earliest phases of solid matter condensation in the solar nebula (chondrites) to material representing asteroidal metamorphism and melting, impact processes on the Moon and even aqueous alteration near the surface of Mars. Meteorites are very rare. Currently many meteorites result from searches in Antarctica and the hot deserts of North Africa and Arabia. The present high find rate likely represents a unique short-term event, asking for a careful management of this scarce scientific resource.
From Supernovae to Planets: The View from Meteorites and Interplanetary Dust Particles
Chondritic meteorites and IDPs retain a record of the prehistory and early history of the Solar System. Chondrites are derived from the asteroid belt, while IDPs probably have both cometary and asteroidal origins. Chondrites and their components contained relatively high levels of short-lived radionuclides when they formed. Some, like 60 Fe, require a stellar source, while others may have formed via energetic particle irradiation in the Solar System. The half-lives of some of the radionuclides are so short (0.1-0.7 My) that if they had a stellar source, this source probably triggered the formation of the Solar System. The high abundance of crystalline circumstellar silicates in IDPs and meteorites, and the relatively low abundance of interstellar organic matter in CI chondrites may result from the thermal processing of interstellar dust seen in YSOs. The oldest dated Solar System objects are the refractory inclusions. The more abundant chondrules seem to have begun forming 1-2 My after refractory inclusions, although there is evidence that chondrules in the CV chondrites began forming contemporaneously with refractory inclusions. Both refractory inclusions and chondrules appear to be the products of transient heating events. The mechanism for making refractory inclusions is uncertain, but in most models refractory inclusions form sunward of the asteroid belt and are then transported outwards either in energetic winds or via turbulent diffusion. At present, the most promising mechanism for making chondrules is shock heating in the asteroid belt. Each chondrite group contains a chemically and/or physically distinct population of chondrules and refractory inclusions. To preserve their distinct chondrule properties from being erased by turbulent diffusion, it is argued that chondrites must have accreted soon after their chondrules formed. However, the variation in the properties of refractory inclusions between chondrites is unexplained. To explain the evidence for aqueous alteration in most chondrites, chondrite formation occurred in the T Tauri phase when temperatures in the asteroid belt allowed for ice to be stable.
Icarus, 2012
Mid-infrared (5 m to 25 m) transmission/absorption spectra of differentiated meteorites (achondrites) were measured to permit comparison with astronomical observations of dust in different stages of evolution of young stellar objects. In contrast to primitive chondrites, achondrites underwent heavy metamorphism and/or extensive melting and represent more advanced stages of planetesimal evolution. Spectra were obtained from primitive achondrites (acapulcoite, winonaite, ureilite, and brachinite) and differentiated achondrites (eucrite, diogenite, aubrite, and mesosiderite silicates). The ureilite and brachinite show spectra dominated by olivine features, and the diogenite and aubrite by pyroxene features. The acapulcoite, winonaite, eucrite, and mesosiderite silicates exhibit more complex spectra, reflecting their multi-phase bulk mineralogy. Mixtures of spectra of the primitive achondrites and differentiated achondrites in various proportions show good similarities to the spectra of the few Myr old protoplanetary disks HD104237A and V410 Anon 13. A spectrum of the differentiated mesosiderite silicates is similar to the spectra of the mature debris disks HD172555 and HD165014. A mixture of spectra of the primitive ureilite and brachinite is similar to the spectrum of the debris disk HD113766. The results raise the possibility that materials produced in the early stage of planetesimal differentiation occur in the protoplanetary and debris disks.
From meteorites to evolution and habitability of planets
Planetary and Space Science, 2012
The evolution of planets is driven by the composition, structure, and thermal state of their internal core, mantle, lithosphere, and crust, and by interactions with a possible ocean and/or atmosphere. A planet's history is a long chronology of events with possibly a sequence of apocalyptic events in which asteroids, comets and their meteorite offspring play an important role. Large meteorite impacts on the young Earth could have contributed to the conditions for life to appear, and similarly large meteorite impacts could also create the conditions to erase life or drastically decrease biodiversity on the surface of the planet. Meteorites also contain valuable information to understand the evolution of a planet through their gas inclusion, their composition, and their cosmogenic isotopes. This paper addresses the evolution of the terrestrial bodies of our Solar System, in particular through all phenomena related to meteorites and what we can learn from them. This includes our present understanding of planet formation, their interior, their atmosphere, and the effects and relations of meteorites with respect to these reservoirs. It brings further insight into the origin and sustainability of life on planets, including Earth. Particular attention is devoted to Earth and Mars, as well as to planets and satellites possessing an atmosphere (Earth, Mars, Venus, and Titan) or a subsurface ocean (e.g., Europa), because those are the best candidates for hosting life. Though the conditions on the planets Earth, Mars, and Venus were probably similar soon after their formation, their histories have diverged about 4 billion years ago. The search for traces of life on early Earth serves as a case study to refine techniques/environments allowing the detection of potential habitats and possible life on other planets. A strong emphasis is placed on impact processes, an obvious shaper of planetary evolution, and on meteorites that document early Solar System evolution and witness the geological processes taking place on other planetary bodies.
2005
Silicate dust entering the solar nebula was overwhelmingly amorphous based on studies of the current interstellar grain population. Moreover, no global high temperature event could have crystallized the dust in the nebula without also destroying the very fragile, noble-gas-rich, carbonaceous presolar grains found in all unaltered primitive meteorites, though more localized heating events undoubtedly occurred. Fine-grained, crystalline silicates in comets, meteorites and IDPs are therefore products of relatively localized thermal and/or aqueous processes and their presence can potentially be used to constrain the metamorphic events that occurred both in the nebula prior to the formation of primitive planetesimals as well as during subsequent parent body processing. As examples, the presence of crystalline magnesium silicates in comets requires both grain annealing and transport out to the nebular environment where comets form (50-200 AU), whereas in primitive chondrite matrices, crystalline Mg-silicates probably formed by evaporation, recondensation and annealing in the inner nebula. Nevertheless, the presence in both IDPs and chondrite matrices of Mn-rich forsterite and enstatite grains with structures indicative of cooling in days shows that identical thermal processes formed some magnesium silicates in comets and asteroids. The bulk of the amorphous material in primitive chondrite matrices may have formed by evaporation and condensation during high temperature chondrule-forming events. Crystalline FeO-rich silicates, such as olivine and phyllosilicates, formed by secondary processes such as thermal metamorphism and aqueous alteration on asteroidal parent bodies and are not the products of primary nebular processes. We explore several such processes and their wider implications for the chemistry of protostellar systems in this chapter.