Meteoritic Research

Besides cometary material collected by sample return spacecraft and interplanetary dust particles (IDPs), primitve meteorites represent an essential source of unaltered material, that conserved its pristine composition and structure since the early times of the solar system. Carbonaceous chondrites like the Murchison and Allende meteorites contain a variety of so-called presolar dust particles that formed in the outflows of Red Giant stars and in ejecta of explosive events, e.g. Supernovae Type II [1]. These minerals survived the formation of the solar system without having been affected by isotope homogenization processes. Thus, isotopic anomalies (compared to the solar values), that are characteristic of the stellar sources of the grains, provide information relevant for numerous fields of modern astrophysics. Among these topics are the evolution of stars and stellar nucleosynthesis [2], convection and mixing processes between different layers in stars [3], particle growth in stellar atmospheres [4], and the chemical evolution of the galaxy [5]. These anomalies are studied with mass spectrometric methods of highest mass resolution and, considering the small sizes of the investigated particles between ~100nm and some mm, of highest lateral resolution. Methods of choice are secondary ion mass spectrometry (SIMS) and resonance ionization mass spectrometry (RIMS), respectively.
learn more Trace Elements in Presolar Dust Grains

The first presolar material identified in primitive meteorites is nanodiamond [6]. In respect of the small sizes of these particles of only a few nanometers, and thus the small number of atoms per particle (a few thousand), mass spectrometric single grain analysis is not possible. Nevertheless, measurements averaging over a large number of crystals can provide information on chemical and structural porperties relevant for astrophysics and nanotechnology.
learn more Quantum Confinement in Meteoritic Nanodiamonds

In addition to presolar minerals, primitive meteorites contain the first solid materials that formed in the early solar system [7]. Up to now, no direct evidence for gas-to-solid condensation processes was found. All known materials that are believed to have formed by condensation were affected by secondary processes. Investigations of the chemical composition and the structure of refractory inlcusions in primitive meteorites offer the potential for revealing details on the very first condensation processes in the early solar system.
learn more Condensation Processes in the Early Solar System

References:

[1] "Interstellar grains in meteorites", U. Ott, Nature 364(1993)25-33.
[2] "Stellar Nucleosynthesis and the Isotopic Composition of Presolar Grains from Primitive Meteorites", E. Zinner, Ann. Rev. Earth Planet. Sci. 26(1998)147-188.
[3] "Nucleosynthesis in Asymptotic Giant Branch Stars: Relevance for Galactic Enrichment and Solar System Formation", M. Busso, R. Gallino and G.J. Wasserburg, Annu. Rev. Astron. Astrophys. 37(1999)239-309.
[4] "Composition and quantities of dust produced by AGB-stars and returned to the interstellar medium", A.S. Ferrarotti und H.-P. Gail, Astron. Astrophys. 447(2006)553-576.
[5] "Placing the Sun and Mainstream SiC Particles in Galactic Chemodynamic Evolution", D.D. Clayton, Astrophys. J. 484(1997)L67-L70.
[6] "Interstellar diamonds in meteorites", R.S. Lewis et al., Nature 326(1987)160-162.
[7] "Lead isotopic ages of chondrules and calcium-aluminum-rich inclusions", Y. Amelin et al., Science 297(2002)1678-1683.

 
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Last update: Wednesday, 02-Nov-2011 17:09:11 CET Email D. Panzer Impressum