Early solar system

These isotopes are sometimes used as tracers of natural terrestrial processes and cycles. Long-lived isotopes, such as Rb and Sm are used for precise dating of geological samples. When the solar system formed it also contained several short-lived isotopes that have since decayed and are now extinct in natural systems. These include Al, Fe, Pu, Pd, and Al with a half-life of less than a million years is particularly important because it is a potentially powerful heat source for planetary bodies and because its existence in the early solar system places tight constraints on the early solar system chronology. 

The Zag meteorite fell in the western Sahara of Morocco in August 1998. This meteorite was unusual in that it contained small crystals of halite (table salt), which experts believe formed by the evaporation of brine (salt water). It is one of the few indications that liquid water, which is essential for the development of life, may have existed in the early solar system. The halite crystals in the meteorite had a remarkably high abundance of 128Xe, a decay product of a short-lived iodine isotope that has long been absent from the solar system. Scientists believe that the iodine existed when the halite crystals formed. The xenon formed when this iodine decayed. For this reason, the Zag meteorite is believed to be one of the oldest artifacts in the solar system. In this lab, you will use potassium-argon radiochemical dating to estimate the age of the Zag meteorite and the solar system. 

An unknown event disturbed the equilibrium of the interstellar cloud, and it collapsed. This process may have been caused by shock waves from a supernova explosion, or by a density wave of a spiral arm of the galaxy. The gas molecules and the particles were compressed, and with increasing compression, both temperature and pressure increased. It is possible that the centrifugal forces due to the rotation of the system prevented a spherical contraction. The result was a relatively flat, rotating disc of matter, in the centre of which was the primeval sun. Analogues of the early solar system, i.e., protoplanetary discs, have been identified from the radiation emitted by T Tauri stars (Koerner, 1997). 

Zinner, E. (2003). An isotopic view of the early solar system. Science, 300, 265-267... 

The presence of 26Mg excesses correlated with Al/Mg ratios in fifteen Ca-Al-rich inclusions from the Allende and Leoville carbonaceous chrondrites has provided additional strong evidence for the in situ decay of 26A1 (see [9] for a recent review of isotopic anomalies). There are also, however, several examples of minerals whose isotopic compositions depart substantially from a unique Al-Mg isochron, even within a single inclusion [10,11]. Since deviations from the isochron may reflect either differences in the formation age of individual minerals or intrinsic heterogeneities in the initial 26A1/27A1 ratio, the value of the Al-Mg system as a chronometer for early solar system events remains unclear. 

Another isotopic anomaly, discovered in Allende inclusions, concerns magnesium, for which an intrinsically low abundance in these samples makes its isotope ratios sensitive to small effects. Certain of the inclusions show a correlation between 26Mg and 27 Al, indicating an origin of excess 26Mg from radioactive decay of 26 A1 (mean life 1 Myr), the existence of which had previously been postulated as a heat source for meteorite parent bodies (Fig. 3.32). Other short-lived activites that seem to have been alive in the early Solar System are 10Be (mean life 2.2 Myr) from a correlation of 10B with 9Be, and 41Ca (mean life 0.15 Myr) from a correlation of... 

ISOLATION OF SOLAR CLOUD LATE INJECTION OF 26AI EARLY SOLAR SYSTEM MATERIAL... 

F. A. Podosek and T. D. Swindle, in J. F. Kerridge and M. S. Matthews (eds.), Meteorites and the Early Solar System, University of Arizona Press, Tucson,... 

Deuterium discovered in interstellar gas (Copernicus satellite) and quantitatively estimated in early Solar System, restricting baryonic density in Big Bang nucleosynthesis (BBNS) theory. 

Refractory materials in primitive meteorites were investigated first as they have the best chance of escaping homogenization in the early solar system. Inclusions in C3 carbonaceous chondrites exhibit widespread anomalies for oxygen and the iron group elements. Only a few members, dubbed FUN (for Fractionated and Unknown Nuclear effects), also display anomalous compositions for the heavy elements. Anomalies in inclusions have generally been connected with explosive or supernova nucleosynthesis. 

A number of now extinct radioactive isotopes have existed in the early solar system. This is shown by the variations that they induce in the abundances in their daughter nuclides. Their main use is in establishing a chronology between their parental presolar stellar sources, and the formation of the solar system and the planets. An active debate is presently going on whether some of these short-lived nuclides could have been made within the early solar system by an intense flux of energetic protons from the young sun. 

THE ISOTOPIC HETEROGENEITY IN THE REFRACTORY COMPONENTS OF THE EARLY SOLAR-SYSTEM... 

Inclusions of the CV3 led to the search for isotopic signatures of individual nucleosynthetic processes, or at least for components closer to the original signature than average solar compositions. They have also begun to demonstrate the isotopic variability of matter emerging from these processes in agreement with astrophysical and astronomical expectations. The principal features of inclusions are an up to 4% 0 enriched reservoir in the early solar system, variations in a component produced in a nuclear neutron-rich statistical equilibrium, and variations in the contribution of p- and r-process products to the heavy elements. 

THE ISOTOPIC HETEROGENEITY IN NON-REFRACTORY EARLY SOLAR SYSTEM MATERIALS... 

Most of the Cr found in the solar system is produced in presupemova neutron-poor nuclear statistical equilibrium as Mn which then decays to Cr (Hainebach et al. 1974 Hartmann et al. 1985). The first evidence for the presence of Mn in the early solar system... 

Birck JL, Allegre CJ (1988) Manganese chromium isotope systematics and development of the early solar system. Nature 331 579-584... 

Birck JL, Rotaru M, Allegre CJ (1999) Mn- Cr evolution of the early solar system. Geochim Cosmochim Acta 63 4111-4117... 

Busfield A, Gilmour JD, Whitby JA, Turner G (2004) Iodine-xenon analysis of ordinary chondrite halide implications for early solar system water. Geochim Cosmochim Acta 68 195-202 Busso M, Gallino R, Wasserburg GJ (1999) Nucleosynthesis in asymptotic giant branch stars relevance for galactic enrichment and solar system formation. Annu Rev Astronom Astrophys 37 239-309 Cameron AGW (1969) Physical conditions in the primitive solar nebula. In Meteorite Research. Millman PM (ed) Reidel, Dordrecht, p 7-12... 

Clayton DD (1989) Origin of heavy xenon in meteoritic diamonds. Astrophys J 340 613-619 Clayton DD, Dwek E, Woosley SE (1977a) Isotopic anomalies and proton irradiation in the early solar system. Astrophys J 214 300-315... 

Dai ZR, Bradley JP, Joswiak DJ, Brownlee DE, Hill HGM, Genge MJ (2002) Possible in-situ formation of meteoritic nanodiamonds in the early Solar System. Nature 418 157-159 Dauphas N, Marty B, Reisberg L (2002) Molybdenum nucleosynthetic dichotomy revealed in primitive meteorites. Astrophys J 569 L139-L142... 

Harper CL (1996) Evidence for Nb in the early solar system and evaluation of a new p-process cosmochronometer from Nb/ Mo. Astrophys J 466 437-456 Harper CL, Wiesmann H, Nyquist LE, Hartmann D, Meyer B, Howard WM (1991) Interpretation of the Ti- Zr anomaly correlation in CAI NNSE Zr production limits and S/ R/ P decomposition of the bulk solar system abundances. Lunar Planet Sci XXII 517-518... 

Hidaka H, Ohta Y, Yoneda S, DeLaeter JR (2001) Isotopic search for live Cs in the early solar system and possibility of Cs- Ba chronometer. Earth Planet Sci Lett 193 459-466 Hinton RW, Bischofif A (1984) Ion microprobe magnesium isotope analysis of plagioclase and hibonite from ordinary chondrites. Nature 308 169-172... 

Kelly WR, Wasserburg GJ (1978) Evidence for the existence of Pd in the early solar system. Geophys Res Lett 5 1079-1082... 

Lee DC, Halliday AN (1996) Hf-W Isotopic evidence for rapid accretion and differentiation in the early solar system. Science 274 1876-1879... 

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