^1,2S. A. Jacobson, ¹A. Morbidelli
¹Laboratoire Lagrange, UNSA, OCA, CNRS, Boulevard de l’Observatoire, BP 4029, 06304 Nice Cedex 4, France
²Universität Bayreuth, Bayerisches Geoinstitut, Bayreuth 95440 Germany

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Reference
Jacobson SA, Morbidelli A (2014) Lunar and terrestrial planet formation in the Grand Tack Scenario. Philosophical Transactions of the Royal Society A 13, 372, 2024
Link to Article [doi: 10.1098/rsta.2013.0174]

¹William K. Hartmann
¹Planetary Science Institute, 1700 East Fort Lowell Road, Suite 106, Tucson, AZ 85719-2395, USA

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Reference
Hartmann WK (2014) The giant impact hypothesis: past, present (and future?). Philosophical Transactions of the Royal Society A 13,372, 2024
Link to Article [doi: 10.1098/rsta.2013.0249]

¹Jiří Borovička, ¹Pavel Koten, ¹Lukáš Shrbený, ¹Rostislav Štork, ¹Kamil Hornoch
¹Astronomical Institute, Academy of Sciences, 251 65, Ondřejov Observatory, Czech Republic

We currently do not have a copyright agreement with this publisher and cannot publish the abstract here

Reference
Borovička J, Koten P, Shrbený L, Štork R, Hornoch K (2014) Spectral, Photometric, and Dynamic Analysis of Eight Draconid Meteors. Earth, Moon, and Planets (in Press).
Link to Article [10.1007/s11038-014-9442-x]

¹Gokce Ustunisik, ^1,2Denton S. Ebel, ^1,2David Walker, ^1,3Joseph S. Boesenberg
¹ Department of Earth and Planetary Sciences, American Museum of Natural History, New York, NY, 10024-5192, U.S.A
² Department of Earth and Environmental Sciences, Lamont Doherty Earth Observatory of Columbia University, Palisades, NY, 10964-8000, U.S.A
³ Department of Geological Sciences, Brown University, Providence, RI, 02912, U.S.A

Condensation models describe the equilibrium distribution of elements between coexisting phases (mineral solid solutions, silicate liquid, and vapor) in a closed chemical system, where the vapor phase is always present, using equations of state of the phases involved at a fixed total pressure (< 1 bar) and temperature (T). The VAPORS code uses a CaO-MgO-Al2O3-SiO2 (CMAS) liquid model at T above the stability field of olivine, and the MELTS thermodynamics algorithm at lower T. Quenched high-T crystal + liquid assemblages are preserved in meteorites as Type B Ca-, Al-rich inclusions (CAIs), and olivine-rich ferromagnesian chondrules. Experimental tests of compositional regions within 100K of the predicted T of olivine stability may clarify the nature of the phases present, the phase boundaries, and the partition of trace elements among these phases. Twenty-three Pt-loop equilibrium experiments in seven phase fields on twelve bulk compositions at specific T and dust enrichment factors tested the predicted stability fields of forsteritic olivine (Mg2SiO4), enstatite (MgSiO3), Cr-bearing spinel (MgAl2O4), perovskite (CaTiO3), melilite (Ca2Al2SiO7 – Ca2Mg2Si2O7) and/or grossite (CaAl4O7) crystallizing from liquid. Experimental results for forsterite, enstatite, and grossite are in very good agreement with predictions, both in chemistry and phase abundances. On the other hand the stability of spinel with olivine, and stability of perovskite and gehlenite are quite different from predictions. Perovskite is absent in all experiments. Even at low oxygen fugacity (IW-3.4), the most TiO2-rich experiments do not crystallize Al-, Ti-bearing calcic pyroxene. The stability of spinel and olivine together is limited to a smaller phase field than is predicted. The melilite stability field is much larger than predicted, indicating a deficiency of current liquid or melilite activity models. In that respect, these experiments contribute to improving the data for calibrating thermodynamic models including MELTS.

Reference
Ustunisik G, Ebel DS, Walker D, Boesenberg JS (2014) Experimental investigation of condensation predictions for dust-enriched Systems. Geochimica et Cosmochimica Acta (in Press).
Link to Article [DOI: 10.1016/j.gca.2014.07.029]

Copyright Elsevier

¹Maria Lugaro, ^1,2,3 Alexander Heger, ¹ Dean Osrin, ⁴ Stephane Goriely,⁵ Kai Zuber, ^6,7 Amanda I. Karakas, ^8,8,10 Brad K. Gibson, ¹ Carolyn L. Doherty, ¹ John C. Lattanzio, ¹¹ Ulrich Ott

¹Monash Centre for Astrophysics (MoCA), Monash University, Clayton VIC 3800, Australia.
²Joint Institute for Nuclear Astrophysics (JINA), 225 Nieuwland Science Hall, Department of Physics, University of Notre Dame, Notre Dame, IN 46556-5670, USA.
³School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455, USA.
⁴Institut d’Astronomie et d’Astrophysique, Université Libre de Bruxelles, CP-226, 1050, Brussels, Belgium.
⁵Institut für Kern- und Teilchenphysik, Technische Universität Dresden, 01069 Dresden, Germany.
⁶Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611, Australia.
⁷Kavli Institute for the Physics and Mathematics of the Universe (WPI), Todai Institutes for Advanced Study, the University of Tokyo, Japan.
⁸Jeremiah Horrocks Institute, University of Central Lancashire, Preston, PR1 2HE, UK.
⁹Institute for Computational Astrophysics, Department of Astronomy and Physics, Saint Mary’s University, Halifax, NS, BH3 3C3, Canada.
¹⁰UK Network for Bridging Disciplines of Galactic Chemical Evolution (BRIDGCE), http://www.astro.keele.ac.uk/bridgce, UK.
¹¹Faculty of Natural Science, University of West Hungary, 9700 Szombathely, Hungary.

Among the short-lived radioactive nuclei inferred to be present in the early solar system via meteoritic analyses, there are several heavier than iron whose stellar origin has been poorly understood. In particular, the abundances inferred for 182Hf (half-life = 8.9 million years) and 129I (half-life = 15.7 million years) are in disagreement with each other if both nuclei are produced by the rapid neutron-capture process. Here, we demonstrate that contrary to previous assumption, the slow neutron-capture process in asymptotic giant branch stars produces 182Hf. This has allowed us to date the last rapid and slow neutron-capture events that contaminated the solar system material at ∼100 million years and ∼30 million years, respectively, before the formation of the Sun.

Reference
Lugaro M, Heger A, Osrin D, Goriely S, Zuber K, Karakas AI, Gibson BK, Doherty CL, Lattanzio JC, Ott U (2014) Stellar origin of the 182Hf cosmochronometer and the presolar history of solar system matter. Science 345:6197, 650-653.
Link to Article [DOI: 10.1126/science.1253338]

Reprinted with permission from AAAS

¹Jilly, C. E., ¹Huss, G. R., ¹Krot, A. N., ¹Nagashima, ²K., Yin, Q.-Z.,³Sugiura, N.

¹Hawai‘i Institute of Geophysics and Planetology, University of Hawai‘i at Mānoa, Honolulu, Hawai‘i, USA
²Department of Earth and Planetary Sciences, University of California, Davis, Davis, California, USA
³Department of Earth and Planetary Science, Graduate School of Science, the University of Tokyo, Bunkyo-ku, Tokyo, Japan

Radiometric dating of secondary minerals can be used to constrain the timing of aqueous alteration on meteoritic parent bodies. Dolomite is a well-documented secondary mineral in CM chondrites, and is thought to have formed by precipitation from an aqueous fluid on the CM parent body within several million years of accretion. The petrographic context of crosscutting dolomite veins indicates that aqueous alteration occurred in situ, rather than in the nebular setting. Here, we present 53Mn-53Cr systematics for dolomite grains in Sutter’s Mill section SM51-1. The Mn-Cr isotope data show well-resolved excesses of 53Cr correlated with 55Mn/52Cr ratio, which we interpret as evidence for the in situ decay of radioactive 53Mn. After correcting for the relative sensitivities of Mn and Cr using a synthetic Mn- and Cr-bearing calcite standard, the data yield an isochron with slope corresponding to an initial 53Mn/55Mn ratio of 3.42 ± 0.86 × 10−6. The reported error includes systematic uncertainty from the relative sensitivity factor. When calculated relative to the U-corrected Pb-Pb absolute age of the D’Orbigny angrite, Sutter’s Mill dolomites give a formation age between 4564.8 and 4562.2 Ma (2.4–5.0 Myr after the birth of the solar system). This age is contemporaneous with previously reported ages for secondary carbonates in CM and CI chondrites. Consistent carbonate precipitation ages between the carbonaceous chondrite groups suggest that aqueous alteration was a common process during the early stages of parent body formation, probably occurring via heating from internal 26Al decay. The high-precision isochron for Sutter’s Mill dolomite indicates that late-stage processing did not reach temperatures that were high enough to further disturb the Mn-Cr isochron.

Reference
Jilly CE, Huss GR, Krot AN, Nagashima K, Yin Q-Z, Sugiura N (2014) 53Mn-53Cr dating of aqueously formed carbonates in the CM2 lithology of the Sutter’s Mill carbonaceous chondrite. Meteoritics & Planetary Science (in Press).
Link to Article [doi: 10.1111/maps.12305]

Published by arrangement with John Wiley & Sons

¹Dobrică, E., ¹Brearley, A. J.
¹Department of Earth and Planetary Sciences MSC03-2040, University of New Mexico, Albuquerque, New Mexico, USA

Mineralogic, textural, and compositional studies of black and white matrices in the unequilibrated ordinary chondrite Tieschitz (H/L, 3.6) show, for the first time in an ordinary chondrite, the presence of widespread, randomly distributed geode-like voids and veins. Scanning electron microscope (SEM) and transmission electron microscope (TEM) studies show that these voids and veins are partially or completely filled by sodic–calcic amphiboles (winchite and barroisite). The occurrence of amphiboles provides unequivocal evidence of the involvement of fluids in the metamorphic evolution of the parent body of Tieschitz. The presence of amphiboles as the main hydrous phases, rather than phyllosilicates, indicates that aqueous fluids were present at or close to the peak of thermal metamorphism, rather than during the waning stages of the cooling history of the parent body. In addition, ferrous olivine crystals, in association with the amphibole, also establish an important link between thermal metamorphism and hydrous phases formed at high temperatures. Mineralogic and textural evidence suggests that the white matrix and amphibole formed contemporaneously from the same hydrous fluid, prior to the formation of ferrous olivine crystals. Additionally, a dark inclusion identified in the host chondrite has mineralogic, petrologic, and bulk chemical characteristics that are similar to the black matrix of host Tieschitz, suggesting that this dark inclusion was emplaced before or during parent body metamorphism.

Reference
Dobrică E, Brearley AJ (2014) Widespread hydrothermal alteration minerals in the fine-grained matrices of the Tieschitz unequilibrated ordinary chondrite. Meteoritics & Planetary Science (in Press).
Link to Article [doi: 10.1111/maps.12335]

Published in Arrangement with John Wiley & Sons

^1,2Jenniskens, P. et al. (>10)*
*Find the extensive, full author and affiliation list on the publishers website.
¹SETI Institute, Carl Sagan Center, Mountain View, California, USA
²NASA Ames Research Center, Moffett Field, California, USA

The Novato L6 chondrite fragmental breccia fell in California on 17 October 2012, and was recovered after the Cameras for Allsky Meteor Surveillance (CAMS) project determined the meteor’s trajectory between 95 and 46 km altitude. The final fragmentation from 42 to 22 km altitude was exceptionally well documented by digital photographs. The first sample was recovered before rain hit the area. First results from a consortium study of the meteorite’s characterization, cosmogenic and radiogenic nuclides, origin, and conditions of the fall are presented. Some meteorites did not retain fusion crust and show evidence of spallation. Before entry, the meteoroid was 35 ± 5 cm in diameter (mass 80 ± 35 kg) with a cosmic-ray exposure age of 9 ± 1 Ma, if it had a one-stage exposure history. A two-stage exposure history is more likely, with lower shielding in the last few Ma. Thermoluminescence data suggest a collision event within the last ∼0.1 Ma. Novato probably belonged to the class of shocked L chondrites that have a common shock age of 470 Ma, based on the U,Th-He age of 420 ± 220 Ma. The measured orbits of Novato, Jesenice, and Innisfree are consistent with a proposed origin of these shocked L chondrites in the Gefion asteroid family, perhaps directly via the 5:2 mean-motion resonance with Jupiter. Novato experienced a stronger compaction than did other L6 chondrites of shock-stage S4. Despite this, a freshly broken surface shows a wide range of organic compounds.

Reference
Jenniskens P et al. (2014) Fall, recovery, and characterization of the Novato L6 chondrite breccia. Meteoritics & Planetary Science (in Press)
Link to Article [doi: 10.1111/maps.12323]

Published by arrangement with John Wiley & Sons

¹Maksimova, A.A., ^1,2Oshtrakh, M.I., ³Klencsár, Z., ¹Petrova, E.V., ¹Grokhovsky, V.I., ⁴Kuzmann, E., ⁴Homonnay, Z., ^1,2Semionkin, V.A.

¹ Department of Physical Techniques and Devices for Quality Control, Institute of Physics and Technology, Ural Federal University, Ekaterinburg 620002, Russian Federation
² Department of Experimental Physics, Institute of Physics and Technology, Ural Federal University, Ekaterinburg 620002, Russian Federation
³ Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, Budapest 1117, Hungary
⁴ Institute of Chemistry, Eötvös Loránd University, Budapest, Hungary

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Reference
Maksimova AA, Oshtrakh MI, Klencsár Z, Petrova EV, Grokhovsky VI, Kuzmann E, Homonnay Z, Semionkin VA (2014) A comparative study of troilite in bulk ordinary chondrites Farmington L5, Tsarev L5 and Chelyabinsk LL5 using Mössbauer spectroscopy with a high velocity Resolution. Journal of Molecular Structure (in Press).

Link to Article [DOI: 10.1016/j.molstruc.2014.05.049]

¹M. Jura, ¹B. Klein, ¹S. Xu (许偲艺), ²E. D. Young
¹ Department of Physics and Astronomy, University of California, Los Angeles, CA 90095-1562, USA
² Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, CA 90095, USA

Relative to calcium, both strontium and barium are markedly enriched in Earth’s continental crust compared to the basaltic crusts of other differentiated rocky bodies within the solar system. Here, we both re-examine available archived Keck spectra to place upper bounds on n(Ba)/n(Ca) and revisit published results for n(Sr)/n(Ca) in two white dwarfs that have accreted rocky planetesimals. We find that at most only a small fraction of the pollution is from crustal material that has experienced the distinctive elemental enhancements induced by Earth-analog plate tectonics. In view of the intense theoretical interest in the physical structure of extrasolar rocky planets, this search should be extended to additional targets.

Reference
Jura M, Klein B, Xu S (许偲艺), Young ED (2014) A Pilot Search for Evidence of Extrasolar Earth-analog Plate Tectonics. Astrophysical Journal Letters 791, L29.

Link to Article [doi:10.1088/2041-8205/791/2/L29]