Noble Gases in the Murchison Meteorite: Possible Relics of s-Process Nucleosynthesis

  title={Noble Gases in the Murchison Meteorite: Possible Relics of s-Process Nucleosynthesis},
  author={Balaji Srinivasan and Edward Anders},
  pages={51 - 56}
The Murchison carbonaceous chondrite contains a new type of xenon component, enriched by up to 50 percent in five of the nine stable xenon isotopes, mass numbers 128 to 132. This component, comprising 5 x 10-5 of the total xenon in the meteorite, is released at 1200� to 1600�C from a severely etched mineral fraction, and probably resides in some refractory mineral. Krypton shows a similar but smaller enrichment in the isotopes 80 and 82. Neon and helium released in the same interval also are… 
Interstellar grains in meteorites: II. SiC and its noble gases
Abstract We have analyzed He, Ne, Ar, Kr, and Xe in fourteen size fractions of interstellar SiC, isolated from the Murchison C2 chondrite. All are mixtures of a highly anomalous component bearing the
Isotopic anomalies of noble gases in meteorites and their origins—III. LL-chondrites
Nine LL-chondrites were studied by a selective etching technique, to characterize the noblegas components in three mineral fractions: HF-HCl-solubles (silicates, metal, troilite, etc.; comprising ∼
S-process krypton of variable isotopic composition in the Murchison meteorite
It is shown that this s-Kr in a residue from Murchison meteorite did not originate in one single s-process but rather is a mixture of contributions from stellar environments where the density of free neutrons was not the same.
Interstellar Grains in Primitive Meteorites: Diamond, Silicon Carbide, and Graphite
Primitive meteorites contain a few parts per million (ppm) of pristine interstellar grains that provide information on nuclear and chemical processes in stars. Their interstellar origin is proven by
Plutonium-244 fission xenon and primordial xenon in lunar samples and meteorites
Xenon found in lunar samples is a binary mixture of244Pu fission xenon and a trapped xenon, whose isotopic composition often shows a striking resemblance to that ofTakaoka's1 primitive xenon. The
Host phases and origin of noble gases in meteorites
A large fraction of the noble gases in carbonaceous chondrites are concentrated in a small amount of meteoritic matter (≲ 2%). It consists of carbon (in different forms) and chromite which are the
Interstellar SiC in the Murchison and Murray meteorites - Isotopic composition of Ne, Xe, Si, C, and N
Abstract Five SiC fractions were isolated from the Murray and Murchison C2 chondrites, and were examined by noble-gas and ion-probe mass spectrometry as well as by SEM-EDX. The SiC (totalling ~6–9
Presolar Diamond in Meteorites
  • S. Amari
  • Physics
    Publications of the Astronomical Society of Australia
  • 2009
Abstract Presolar diamond, the carrier of the isotopically anomalous Xe component Xe–HL, was the first mineral type of presolar dust that was isolated from meteorites. The excesses in the light,
▪ Abstract Primitive meteorites contain grains of stardust that originated from stellar outflows and supernova ejecta prior to the formation of the Solar System. The study of these grains in the
Silicon Isotopic Composition in Large Meteoritic SiC Particles and 22Na Origin of 22Ne
Calculations show that the silicon isotope correlations in those large SiC particles can be generated only in the most massive carbon stars, and that the almost pure neon-22 (22Ne) in those particles must be interpreted as the condensation of radioactive sodium- 22 (22Na) in the particles as they flowed away from the stars.


Host Phase of a Strange Xenon Component in Allende
The host phase of an enigmatic Xe component in the Allende meteorite, which may have been produced by spontaneous fission of an extinct super-heavy element has been isolated. The fission Xe resides
Extinct Superheavy Element in the Allende Meteorite
An effort has been made to identify the extinct superheavy element that was present in meteorites and decayed to 131-136Xe by spontaneous fission. To characterize its chemical properties, we have
Allende meteorite: Isotopically anomalous xenon is accompanied by normal osmium.
The (184)Os/(190)Os ratio of six Allende meteorite samples was determined by neutron activation analysis, and it seems very unlikely that the xenon anomalies were produced in a supernova by the p and r processes.
On the origins of trapped helium, neon and argon isotopic variations in meteorites—II. Carbonaceous meteorites
Abstract Data are presented from stepwise heating experiments on five carbonaceous chondrites: Alais, Ivuna, Orgueil, Cold Bokkeveld and Nogoya. The data indicate the presence of two isotopically
Noble gases in the Allende and Abee meteorites and a gas-rich mineral fraction: investigation by stepwise heating
Abstract Noble gases in three meteoritic samples were examined by stepwise heating, in an attempt to relate peaks in the outgassing curves to specific minerals: NeKrXe in Allende (C3V) and an Allende
Primordial noble gases in separated meteoritic minerals—I
Abstract Magnetite and a layer-lattice silicate from the Orgueil carbonaceous chondrite show strikingly different noble gas patterns. Magnetite contains He, Ne and Ar in essentially solar
Excess 16 O, relative to terrestrial abundances, has been found in all samples of C2, C3 and C4 carbonaceous chondrites which have been analyzed, amounting to nine meteorites thus far. Whole-rocks
A neon-E-rich phase in the Orgueil carbonaceous chondrite
Abstract A procedure has been developed for separating a silicate fraction, heavily enriched in neon-E, from the carbonaceous chondrite Orgueil. The trapped neon in this fraction has a20Ne/22Ne ratio
Gas-rich minerals in the Allende meteorite: Attempted chemical characterization
A ten-step etching experiment with HNO 3 was performed on a chromite-carbon residue from Allende, in order to characterize the HNO 3 -soluble, minor phase “Q” that contains most of the primordial Ar,
Condensation in supernova ejecta and isotopic anomalies in meteorites
Some of the observed isotopic anomalies in meteorites may be due to presolar grains that originated in supernova explosions. This hypothesis is investigated by performing chemical equilibrium