Li and B isotopic variations in an Allende CAI: Evidence for the in situ decay of short-lived 10Be and for the possible presence of the short-lived nuclide 7Be in the early solar system

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.

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Short-Lived Nuclei in the Early Solar System: A Low Mass Stellar Source?

Publications of the Astronomical Society of Australia ◽

10.1071/as03035 ◽

2003 ◽

Vol 20 (4) ◽

pp. 356-370 ◽

Cited By ~ 45

Author(s):

M. Busso ◽

R. Gallino ◽

G. J. Wasserburg

Keyword(s):

Solar System ◽

Asymptotic Giant Branch ◽

Early Solar System ◽

Uncertainty Range ◽

System A ◽

Free Decay ◽

Low Mass ◽

Stellar Source ◽

Review Current

AbstractWe discuss possible stellar origins of short-lived radioactive nuclei with meanlife τ ≤ 100 Myr, which were shown to be alive in the Early Solar System (ESS). We first review current ideas on the production of nuclides having 10 ≤ τ ≤ 100 Myr, which presumably derive from the continuous interplay of galactic astration, nucleosynthesis from massive supernovae and free decay in the interstellar medium. The abundance of the shorter lived 53Mn might be explained by this same scenario. Then we consider the nuclei 107Pd, 26Al, 41Ca and 60Fe, whose early solar system abundances are too high to have originated in this way. Present evidence favours a stellar origin, particularly for 107Pd, 26Al and 60Fe, rather than an in situ production by energetic solar particles. The idea of an encounter (rather close in time and space) between the forming Sun and a dying star is therefore discussed: this star may or may not have also triggered the solar formation. Recent nucleosynthesis calculations for the yields of the relevant short-lived isotopes and of their stable reference nuclei are discussed. Massive stars evolving to type II supernovae (either leaving a neutron star or a black hole as a remnant) seem incapable of explaining the four most critical ESS radioactivities in their observed abundance ratios. An asymptotic giant branch (AGB) star seems to be a viable source, especially if of relatively low initial mass (M ≤ 3 M⊙) and with low neutron exposure: this model can provide a solution for 26Al, 41Ca and 107Pd, with important contributions to 60Fe, which are inside the present uncertainty range of the 60Fe early solar system abundance. Such a model requires that 26Al is produced substantially on the AGB by cool bottom processing. The remaining inventory of short-lived species in the solar nebula would then be attributed to the continuous galactic processing, with the exception of 10Be, which must reflect production by later proton bombardment at a low level during early solar history.

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Circumstellar disks in high-mass star environments: the early solar system

Proceedings of the International Astronomical Union ◽

10.1017/s1743921310011336 ◽

2009 ◽

Vol 5 (H15) ◽

pp. 746-747

Author(s):

Thierry Montmerle ◽

Matthieu Gounelle ◽

Georges Meynet

Keyword(s):

Solar System ◽

Circumstellar Disks ◽

Energetic Particles ◽

High Mass ◽

Circumstellar Disk ◽

Mass Star ◽

Early Solar System ◽

Explosive Nucleosynthesis ◽

By Products

AbstractThe early solar system represents the only case we have of a circumstellar disk that can be investigated “in situ” -albeit 4.6 Gyr after its formation. Meteorites studies give mounting evidence for an intense irradiation phase of the young circumsolar disk by energetic particles, and also for contamination by products of high-mass stellar and/or explosive nucleosynthesis. We thus discuss the conditions of the birth of the solar system in a high-mass star environment.

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Curious kinetic behavior in silica polymorphs solves seifertite puzzle in shocked meteorite

Science Advances ◽

10.1126/sciadv.1500075 ◽

2015 ◽

Vol 1 (4) ◽

pp. e1500075 ◽

Cited By ~ 18

Author(s):

Tomoaki Kubo ◽

Takumi Kato ◽

Yuji Higo ◽

Ken-ichi Funakoshi

Keyword(s):

High Pressure ◽

Solar System ◽

Shock Duration ◽

Kinetic Behavior ◽

Early Solar System ◽

X Ray Diffraction ◽

X Ray

The presence of seifertite, one of the high-pressure polymorphs of silica, in achondritic shocked meteorites has been problematic because this phase is thermodynamically stable at more than ~100 GPa, unrealistically high-pressure conditions for the shock events in the early solar system. We conducted in situ x-ray diffraction measurements at high pressure and temperatures, and found that it metastably appears down to ~11 GPa owing to the clear difference in kinetics between the metastable seifertite and stable stishovite formations. The temperature-insensitive but time-sensitive kinetics for the formation of seifertite uniquely constrains that the critical shock duration and size of the impactor on differentiated parental bodies are at least ~0.01 s and ~50 to 100 m, respectively, from the presence of seifertite.

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The selenium isotopic variations in chondrites are mass-dependent; Implications for sulfide formation in the early solar system

Earth and Planetary Science Letters ◽

10.1016/j.epsl.2017.10.032 ◽

2018 ◽

Vol 481 ◽

pp. 212-222 ◽

Cited By ~ 14

Author(s):

J. Labidi ◽

S. König ◽

T. Kurzawa ◽

A. Yierpan ◽

R. Schoenberg

Keyword(s):

Solar System ◽

Early Solar System ◽

Mass Dependent ◽

Isotopic Variations

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Molecular, isotopic and in situ analytical approaches to the study of meteoritic organic material

International Journal of Astrobiology ◽

10.1017/s1473550404002046 ◽

2004 ◽

Vol 3 (2) ◽

pp. 107-116 ◽

Cited By ~ 1

Author(s):

Jonathan S. Watson ◽

Victoria K. Pearson ◽

Mark A. Sephton ◽

Iain Gilmour

Keyword(s):

Organic Matter ◽

Solar System ◽

Interstellar Space ◽

Early Solar System ◽

Stable Isotopic ◽

Isotopic Studies ◽

Biological Sources ◽

Analytical Approaches

Organic materials isolated from carbonaceous meteorites provide us with a record of pre-biotic chemistry in the early Solar System. Molecular, isotopic and in situ studies of these materials suggest that a number of extraterrestrial environments have contributed to the inventory of organic matter in the early Solar System including interstellar space, the Solar nebula and meteorite parent bodies.There are several difficulties that have to be overcome in the study of the organic constituents of meteorites. Contamination by terrestrial biogenic organic matter is an ever-present concern and a wide variety of contaminant molecules have been isolated and identified including essential plant oils, derived from either biological sources or common cleaning products, and aliphatic hydrocarbons, most probably derived from petroleum-derived pollutants. Only 25% of the organic matter in carbonaceous chondrites is amenable to extraction with organic solvents; the remainder is present as a complex macromolecular aromatic network that has required the development of analytical approaches that can yield structural and isotopic information on this highly complex material.Stable isotopic studies have been of paramount importance in understanding the origins of meteoritic organic matter and have provided evidence for the incorporation of interstellar molecules within meteoritic material. Extending isotopic studies to the molecular level is yielding new insights into both the sources of meteoritic organic matter and the processes that have modified it.Organic matter in meteorites is intimately associated with silicate minerals and the in situ examination of the relationships between organic and inorganic components is crucial to our understanding of the role of asteroidal processes in the modification of organic matter and, in particular, the role of water as both a solvent and a reactant on meteorite parent bodies.

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