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Schulman LS. Low Entropy Future Boundary Conditions. ENTROPY 2022; 24:e24070976. [PMID: 35885200 PMCID: PMC9323633 DOI: 10.3390/e24070976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 07/06/2022] [Accepted: 07/12/2022] [Indexed: 02/05/2023]
Abstract
A number of ways to detect future, low-entropy, boundary conditions are considered. The most important of these is the use of slowly-decaying isotopes and the observation (or prediction) of galactic dynamics. There is the expectation that future developments in experimental or observational technique will yield positive results.
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Pravdivtseva O, Tissot FLH, Dauphas N, Amari S. Evidence of presolar SiC in the Allende Curious Marie calcium aluminum rich inclusion. NATURE ASTRONOMY 2020; 2020:10.1038/s41550-019-1000-z. [PMID: 32021908 PMCID: PMC6999789 DOI: 10.1038/s41550-019-1000-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 12/06/2019] [Indexed: 06/10/2023]
Abstract
Calcium aluminum rich inclusions (CAIs) are one of the first solids to have condensed in the solar nebula, while presolar grains formed in various evolved stellar environments. It is generally accepted that CAIs formed close to the Sun at temperatures above 1500 K, where presolar grains could not survive, and were then transported to other regions of the nebula where the accretion of planetesimals took place. In this context, a commonly held view is that presolar grains are found solely in the fine-grained rims surrounding chondrules and in the low-temperature fine-grained matrix that binds the various meteoritic components together. Here we demonstrate, based on noble gas isotopic signatures, that presolar SiC have been incorporated into fine-grained CAIs in the Allende carbonaceous chondrite at the time of their formation, and have survived parent body processing. This finding provides new clues on the conditions in the nascent solar system at the condensation of first solids.
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Affiliation(s)
- O Pravdivtseva
- Physics Department and McDonnell Center for the Space Sciences, Washington University, Saint Louis, MO 63130, USA
| | - F L H Tissot
- The Isotoparium, Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
| | - N Dauphas
- Origins Laboratory, Department of the Geophysical Sciences and Enrico Fermi Institute, The University of Chicago, Chicago, Il 60637, USA
| | - S Amari
- Physics Department and McDonnell Center for the Space Sciences, Washington University, Saint Louis, MO 63130, USA
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Amari S. Recent Progress in Presolar Grain Studies. Mass Spectrom (Tokyo) 2014; 3:S0042. [PMID: 26819886 DOI: 10.5702/massspectrometry.s0042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Accepted: 11/07/2014] [Indexed: 11/23/2022] Open
Abstract
Presolar grains are stardust that condensed in stellar outflows or stellar ejecta, and was incorporated in meteorites. They remain mostly intact throughout the journey from stars to the earth, keeping information of their birthplaces. Studies of presolar grains, which started in 1987, have produced a wealth of information about nucleosynthesis in stars, mixing in stellar ejecta, and temporal variations of isotopic and elemental abundances in the Galaxy. Recent instrumental advancements in secondary ion mass spectrometry (SIMS) brought about the identification of presolar silicate grains. Isotopic and mineralogical investigations of sub-μm grains have been performed using a combination of SIMS, transmission electron microscopy (TEM) and focused ion beam (FIB) techniques. Two instruments have been developed to study even smaller grains (∼50 nm) and measure isotopes and elements of lower abundances than those in previous studies.
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Affiliation(s)
- Sachiko Amari
- McDonnell Center for the Space Sciences and the Physics Department, Washington University
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Huss GR, Alexander EC. On the presolar origin of the “normal planetary” noble gas component in meteorites. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb092ib04p0e710] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Prettyman TH, Mittlefehldt DW, Yamashita N, Lawrence DJ, Beck AW, Feldman WC, McCoy TJ, McSween HY, Toplis MJ, Titus TN, Tricarico P, Reedy RC, Hendricks JS, Forni O, Le Corre L, Li JY, Mizzon H, Reddy V, Raymond CA, Russell CT. Elemental mapping by Dawn reveals exogenic H in Vesta's regolith. Science 2012; 338:242-6. [PMID: 22997135 DOI: 10.1126/science.1225354] [Citation(s) in RCA: 186] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Using Dawn's Gamma Ray and Neutron Detector, we tested models of Vesta's evolution based on studies of howardite, eucrite, and diogenite (HED) meteorites. Global Fe/O and Fe/Si ratios are consistent with HED compositions. Neutron measurements confirm that a thick, diogenitic lower crust is exposed in the Rheasilvia basin, which is consistent with global magmatic differentiation. Vesta's regolith contains substantial amounts of hydrogen. The highest hydrogen concentrations coincide with older, low-albedo regions near the equator, where water ice is unstable. The young, Rheasilvia basin contains the lowest concentrations. These observations are consistent with gradual accumulation of hydrogen by infall of carbonaceous chondrites--observed as clasts in some howardites--and subsequent removal or burial of this material by large impacts.
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Affiliation(s)
- Thomas H Prettyman
- Planetary Science Institute, 1700 East Fort Lowell, Suite 106, Tucson, AZ 85719-2395, USA.
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Zinner E, Amari S, Wopenka B, Lewis RS. Interstellar graphite in meteorites: Isotopic compositions and structural properties of single graphite grains from Murchison. ACTA ACUST UNITED AC 2012. [DOI: 10.1111/j.1945-5100.1995.tb01115.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Anders E, Zinner E. Interstellar Grains in Primitive Meteorites: Diamond, Silicon Carbide, and Graphite. ACTA ACUST UNITED AC 2012. [DOI: 10.1111/j.1945-5100.1993.tb00274.x] [Citation(s) in RCA: 444] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Whittaker AG, Watts EJ, Lewis RS, Anders E. Carbynes: carriers of primordial noble gases in meteorites. Science 2010; 209:1512-4. [PMID: 17745959 DOI: 10.1126/science.209.4464.1512] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Five carbynes (triply bonded allotropes of carbon) have been found by electron diffraction in the Allende and Murchison carbonaceous chondrites: carbon VI, VIII, X, XI, and (tentatively) XII. From the isotopic composition of the associated noble-gas components, it appears that the carbynes in Allende (C3V chondrite) are local condensates from the solar nebula, whereas at least two carbynes in Murchison (C2 chondrite) are of exotic, presolar origin. They may be dust grains that condensed in stellar envelopes and trapped isotopically anomalous matter from stellar nucleosynthesis.
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The Most Primitive Material in Meteorites. ACTA ACUST UNITED AC 2003. [DOI: 10.1007/3-540-45840-9_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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11
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Hoppe P, Zinner E. Presolar dust grains from meteorites and their stellar sources. ACTA ACUST UNITED AC 2000. [DOI: 10.1029/1999ja900194] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Abstract
Diamond is a remarkable mineral and has been long recognized for its unusual physical and chemical properties: robust and widespread in industry, yet regally adorned. This diversity is even greater than formally appreciated because diamond is recognized as an extraordinary recorder of astrophysical and geodynamic events that extend from the far reaches of space to Earth's deep interior. Many diamonds are natural antiques that formed in presolar supernovae by carbon vapor deposition, in asteroidal impacts and meteorite craters by shock metamorphism, and in Earth's mantle 1 to 2 billion years after planetary accretion from fluids and melts. The carbon in diamond is primordial, but there are unexplained isotopic fractionations and uncertainties in heterogeneity.
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Affiliation(s)
- SE Haggerty
- Department of Geosciences, University of Massachusetts, Amherst, MA 01003, USA
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Manuel O, Windler K, Nolte A, Johannes L, Zirbel J, Ragland D. Strange xenon in Jupiter. J Radioanal Nucl Chem 1998. [DOI: 10.1007/bf02385365] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Kuroda PK, Myers WA. Plutonium-244 fission xenon and primordial xenon in lunar samples and meteorites. J Radioanal Nucl Chem 1998. [DOI: 10.1007/bf02387465] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Plutonium-244 fission xenon and primordial xenon in the Allende meteorite. J Radioanal Nucl Chem 1998. [DOI: 10.1007/bf02387466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Abstract
Although it was well known that a high
13
C abundance was a common feature of the spectra of evolved stars, it took over 50 years to find evidence of carbonaceous instellar dust, which might have been ejected from such objects, in the Solar System. However, it is now established that dust probably produced in novae and red giants can be located in primitive meteorites and the latest state of knowledge in respect of such components is reviewed herein. Nitrogen isotopic measurements have been helpful in distinguishing another form of dust that is carbonaceous but does not have a distinctive
13
C abundance. Likewise they suggest a non-carbonaceous material (possibly a sulphide) present in the meteorite Bencubbin could be a relict of supernovae outbursts. None of the components seen in meteorites can be detected in deep-sea spheres or stratospheric grains to provide a link between interstellar matter and comets. Until now interstellar dust has been the realm of observing astronomers and theoretians; stable isotope measurements are responsible for recognizing a material which it should be possible to isolate and study in the laboratory.
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Myers WA, Kuroda PK. Plutonium-244 and strange xenon components in the solar system. J Radioanal Nucl Chem 1995. [DOI: 10.1007/bf02035974] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Brown LE, Clayton DD. Silicon Isotopic Composition in Large Meteoritic SiC Particles and
22
Na Origin of
22
Ne. Science 1992; 258:970-2. [PMID: 17794592 DOI: 10.1126/science.258.5084.970] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Large silicon carbide (SiC) particles extracted from acid-insoluble residues of carbonaceous chondrites are isotopically anomalous in both silicon and carbon and contain isotopically extreme noble gases. These particles are thought to have originated in mass outflows from red giant stars and to have existed in the interstellar medium at the time the solar system formed from an interstellar cloud. Calculations show that the silicon isotope correlations in those large SiC particles can be generated only in the most massive carbon stars. Consequently, the almost pure neon-22 ((22)Ne) in those particles must be interpreted as the condensation of radioactive sodium-22 ((22)Na) in the particles as they flowed away from the stars. The (22)Na is produced through proton capture by (21)Ne at the base of the surface convection zone. Neon-22 does not exist abundantly in helium shells hot enough to burn magnesium, which is necessary to establish the measured silicon isotopic composition.
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Lewis RS, Amari S, Anders E. Meteoritic silicon carbide: pristine material from carbon stars. Nature 1990. [DOI: 10.1038/348293a0] [Citation(s) in RCA: 112] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Ott U, Begemann F, Yang J, Epstein S. S-process krypton of variable isotopic composition in the Murchison meteorite. Nature 1988; 332:700-2. [PMID: 11542152 DOI: 10.1038/332700a0] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Current theories on the origin of the chemical elements explain the abundance of medium-heavy and heavy nuclides to be due to the capture by pre-existing lighter nuclides of free neutrons on either a slow timescale (s-process) or a rapid timescale (r-process). Experimental evidence in support of these theories comes from the analysis of carbonaceous chondrites. In acid-resistant residues of these meteorites a kind of xenon has been found, the isotopic composition of which matches almost perfectly that predicted for s-process xenon. We report data that allow us, for the first time, to derive with reasonable precision the full isotopic spectrum of s-process krypton as well. We show 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. The astrophysical conditions under which this Krypton has been produced were distinct from those that have been invoked to explain the Solar System s-process abundance. Similar to the 13C-rich carbon component in an aliquot of the same residue, the s-process Kr from different astrophysical sites has retained its identity during the accumulation and subsequent history of the meteorite.
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Affiliation(s)
- U Ott
- Max-Planck Institut fur Chemie, Mainz, FRG
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Composition in Halley’s Comet: Clues to Origin and History of Cometary Matter. REVIEWS IN MODERN ASTRONOMY 1988. [DOI: 10.1007/978-3-642-74188-3_1] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Interstellar Grains in the Solar System. ACTA ACUST UNITED AC 1987. [DOI: 10.1007/978-94-009-3861-8_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Heymann D. Buckminsterfullerene, its siblings, and soot: Carriers of trapped inert gases in meteorites? ACTA ACUST UNITED AC 1986. [DOI: 10.1029/jb091ib13p0e135] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Jones CM, Lumpkin GR, Reynolds JH. Trapped Xe components in etched samples of the Murray (C2) and Murchison (C2) carbonaceous chondrites. ACTA ACUST UNITED AC 1985. [DOI: 10.1029/jb090is02p0c715] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
The Murchison and Allende chondrites contain up to 5 parts per million carbon that is enriched in carbon-13 by up to + 1100 per mil (the ratio of carbon-12 to carbon-13 is approximately 42, compared to 88 to 93 for terrestrial carbon). This "heavy" carbon is associated with neon-22 and with anomalous krypton and xenon showing the signature of the s-process (neutron capture on a slow time scale). It apparently represents interstellar grains ejected from late-type stars. A second anomalous xenon component ("CCFXe") is associated with a distinctive, light carbon (depleted in carbon-13 by 38 per mil), which, however, falls within the terrestrial range and hence may be of either local or exotic origin.
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Oliver L, Ballad R, Richardson J, Manuel O. Isotopically anomalous tellurium in allende: another relic of local element synthesis. ACTA ACUST UNITED AC 1981. [DOI: 10.1016/0022-1902(81)80234-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Ballad RV, Oliver LL, Downing RG, Manuel OK. Isotopes of tellurium, xenon and krypton in Allende meteorite retain record of nucleosynthesis. Nature 1979. [DOI: 10.1038/277615a0] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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