P. Koten^a, J. Vaubaillon^b, D. Čapek^a, V. Vojáček^a, P. Spurný^a, R. Štork^a, F. Colas^b

^aAstronomical Institute of the Academy of Sciences, Ondřejov Observatory, Fričova 298, 25165 Ondřejov, Czech Republic
^bInstitut de Mécanique Céleste et de Calcul des Éphémérides – Observatoire de Paris, 77 avenue Denfert-Rochereau, 75014, Paris, France

The very next year following the fall of Neuschwanstein meteorites and discovery of their orbital similarity with the Příbram meteorite, dedicated observational campaigns aiming for the detection of faint meteors on similar orbits were started. The goal of this paper is to process all the data collected within 7 years, to analyse their atmospheric trajectories and heliocentric orbits and to investigate the possibility that they belong to the stream.

The trajectories and orbits of the detected meteors were used to determine whether those meteors are members of the same shower. An orbital evolution model was applied on a certain number of cloned particles to investigate their possible connection with the meteorite stream. Statistical tests were conducted to determine if such small sample of the orbits is similar by chance or if the stream is real. It was found that from the observational as well as the theoretical point of view it is impossible to prove the existence of faint meteor shower connected with the Příbram and Neuschwanstein meteorite stream.

Reference
Koten P, Vaubaillon J, Čapek D, Vojáček V, Spurný P, Štork R and Colas F (in press) Search for faint meteors on the orbits of Příbram and Neuschwanstein meteorites.  Icarus
[doi:10.1016/j.icarus.2014.06.014]
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Paul H. Warrena, Alan E. Rubina, Junko Isaa, Nicholas Gesslerb, Insu Ahnc, Byeon-Gak Choic

^aInstitute of Geophysics and Planetary Physics, University of California, Los Angeles, CA 90095-1567, USA
^bInformation Science & Information Studies Program, Duke University, Durham, NC 27708 USA
^cEarth Science Education, Seoul National University, Seoul 151-748, Korea

The Northwest Africa 5738 eucrite contains a record of unprecedented geochemical complexity for a sample from the HED asteroid. It originated with a uniquely evolved (Stannern Trend) primary igneous composition, combining ultra-high bulk incompatible element and Na₂O concentrations with a relatively low mg. Its bulk oxygen-isotopic composition (Δ’¹⁷O = – 0.27 ‰), as well as its trace element composition (e.g., Ga/Al), confirm other evidence for classification as a eucrite. Pyroxene mg equilibration, exsolution and “cloudy” inclusions, all reflect a typical eucritic degree of thermal metamorphism. The rock contains an unprecedented array of microscopic fluid-metasomatic vein deposits. Most common are curvy microveins within pyroxene, which consist dominantly of Ca-plagioclase (typically An₉₅, in stark contrast with the rock’s An_68-78 primary-igneous plagioclase), with Fe-olivine (Fo₁₄) and Cr-spinel as additional major constituents. Likely related to these microveins are small masses of intergrown Ca-plagioclase (again roughly An₉₅) and silica (or high-Si glass). Analyses of the microvein Cr-spinels show stoichiometry implying a significant Fe³⁺ content (Fe₂O₃0.7-2.3 wt%), and fO₂ up to roughly IW+3; clearly elevated in comparison to the normal HED fO₂ of about IW-1. The fO₂ results show an anticorrelation with equilibration T (and with Mg/Fe), which suggests the parent fluid system became more oxidizing as it cooled. NWA 5738 also contains apparent secondary iron metal. The Fe-metals are very pure, with Ni consistently below an EPMA detection limit of ∼0.01 wt%. The vein-like shapes of roughly 1/3 of the largest Fe-metals suggest origin by deposition from a fluid. The role of pyroxene exsolution as template for a denticular (sawtooth) Fe-metal edge shape, and the survival of Fo₁₄ olivine in a rock with abundant silica and a far higher bulk mg, suggest that the most intense thermal metamorphism occurred no later than the secondary alteration. Near-complete lack of spatial association suggests that the Fe-metals formed during a distinct time period from the curvy microveins. The immediate cause of Fe-metal deposition was most plausibly (or anyway, least implausibly) an abrupt downshift in the fluid fO₂. Considering the extremely evolved bulk composition, the fluid(s) may have been largely deuteric. However, more likely the main source of fluid was a nearby buried mass of volatile-rich impactor matter, such as carbonaceous chondrite, that hit the asteroid at low enough velocity to remain mostly intact. We further speculate that the abrupt drop in fluid fO₂ may have been caused by a process of carbon-fueled “smelting” (cf. ureilites), triggered by an impact-effected shift of the carbonaceous material to a changed environment, with higher Tand/or lower P. These and other recent eucrite results point to a need for greater scrutiny regarding the absence of comparable alteration-veining in rocks from the lunar highland crust, a mysterious lack in view of recent evidence for abundant lunar water.

Reference
Warren PH, Rubin AE, Isa J, Gessler N, Ahn I and Choi B-G (in press) Northwest Africa 5738: Multistage fluid-driven secondary alteration in an extraordinarily evolved eucrite. Geochimica et Cosmochimica Acta
[doi:10.1016/j.gca.2014.06.008]
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Derek W. G. Sears

NASA Ames Research Center/Bay Area Environmental Research Institute, Space Science and Astrobiology Division, Mountain View, California, USA

Vagn Buchwald (Fig. 1) was born in Copenhagen where he attended school and college. Then after 18 months of military service, he assumed a position at the Technical University of Copenhagen. A few years later, he was presented with a piece of the Cape York meteorite, which led to an interest in iron meteorites. Through a campaign of informed searching, Vagn found the 20 ton Agpalilik meteorite (part of the Cape York shower) on 31st July 1963 and by September 1967 had arranged its transport to Copenhagen. After sorting and describing the Danish collection, which included application of the Fe-Ni-P phase diagram to iron meteorite mineralogy, Vagn was invited to sort and describe other iron meteorite collections. This led to a 7 yr project to write his monumental Handbook of Iron Meteorites. Vagn spent 3 yr in the United States and visited most of the world’s museums, the visit to Berlin being especially important since the war had left their iron meteorites in bad condition and without labels. During a further decade or more of iron meteorite research, he documented natural and anthropomorphic alterations experienced by iron meteorites, discovered five new minerals (roaldite, carlsbergite, akaganeite, hibbingite, and arupite); had a mineral (buchwaldite, NaCaPO₄) and asteroid (3209 Buchwald 1982 BL1) named after him; and led expeditions to Chile, Namibia, and South Africa in search of iron meteorites and information on them. Vagn then turned his attention to archeological metal artifacts. This work resulted in many papers and culminated in two major books on the subject published in 2005 and 2008, after his retirement in 1998. Vagn Buchwald has received numerous Scandinavian awards and honors, and served as president of the Meteoritical Society in 1981–1982.

Reference
Sears DWG (in press) Oral histories in meteoritics and planetary science—XXV: Vagn F. Buchwald. Meteoritics & Planetary Science
[doi:10.1111/maps.12332]
Published by arrangement with John Wiley & Sons

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Danielle Piskorz and David J. Stevenson

Division of Geological and Planetary Sciences, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125

The giant impact hypothesis for the origin of the Moon points to the creation of a hot, young moon, likely with a global magma ocean. Such a magma ocean would produce a flotation crust of plagioclase crystals, or an anorthositic crust. Early calculations of the expected anorthosite content of the lunar highlands crust did not match initial measurements of Apollo samples, and more recently have not matched Clementine measurements or SELENE measurements, because they assumed interstitial melt would freeze. We consider a physical model of a magma ocean with an accumulating flotation lid, and find that significant escape of melt can take place for reasonable physical parameters and timescales of melt migration, even allowing for the inhibiting effect of plausible compaction viscosities. This model permits more nearly pure lunar anorthosites, consistent with observations. The model encounters some difficulty in explaining the expulsion of melt for the near-surface crust (up to five-kilometers’ depth) that presumably dominates the Apollo samples, suggesting that impact mixing and tidal heating are needed to explain the discrepancy.

Reference
Piskorz D and Stevenson DJ (in press) The Formation of Pure Anorthosite on the Moon. Icarus
[doi:10.1016/j.icarus.2014.06.015]
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M. Mommert¹, D. Farnocchia², J. L. Hora³, S. R. Chesley², D. E. Trilling¹, P. W. Chodas², M. Mueller⁴, A. W. Harris⁵, H. A. Smith³ and G. G. Fazio³

¹Department of Physics and Astronomy, Northern Arizona University, P.O. Box 6010, Flagstaff, AZ 86011, USA
²Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
³Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS 65, Cambridge, MA 02138-1516, USA
⁴SRON Netherlands Institute for Space Research, Postbus 800, 9700-AV Groningen, The Netherlands
⁵DLR Institute of Planetary Research, Rutherfordstrasse 2, D-12489 Berlin, Germany

We report on observations of near-Earth asteroid 2011 MD with the Spitzer Space Telescope. We have spent 19.9 hr of observing time with channel 2 (4.5 μm) of the Infrared Array Camera and detected the target within the 2σ positional uncertainty ellipse. Using an asteroid thermophysical model and a model of nongravitational forces acting upon the object, we constrain the physical properties of 2011 MD, based on the measured flux density and available astrometry data. We estimate 2011 MD to be (6) m in diameter with a geometric albedo of 0.3 (uncertainties are 1σ). We find the asteroid’s most probable bulk density to be (1.1) g cm^-3, which implies a total mass of (50–350) t and a macroporosity of ≥65%, assuming a material bulk density typical of non-primitive meteorite materials. A high degree of macroporosity suggests that 2011 MD is a rubble-pile asteroid, the rotation of which is more likely to be retrograde than prograde.

Reference
Mommert M, Farnocchia D, Hora JL, Chesley SR, Trilling DE, Chodas PW, Mueller M, Harris AW, Smith HA and Fazio GG (in press) Physical properties of near-Earth asteroid 2011 MD. The Astrophysical Journal Letters 789:L22.
[doi:10.1088/2041-8205/789/1/L22]
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Valery Shuvalov¹ and Rainer Gersonde²

¹Institute of Geosphere Dynamics RAS, Moscow, Russia
²Alfred Wegener Institut fur Polar- und Meeresforschung, Bremerhaven, Germany

The results of numerical simulations of the Eltanin impact are combined with the available geological data in order to reconstruct the impact dynamics and to get some constraints on the impact parameters. Numerical simulations show that the Eltanin projectile size should be less than 2 km for a 45° oblique impact and less than 1.5 km for a vertical impact. On the other hand, we demonstrate that the projectile diameter cannot be considerably smaller than 1 km; otherwise, the impact-induced water flow cannot transport eroded sediments across large distances. The maximum displacement approximately equals the water crater radius and rapidly decreases with increasing distances. Numerical simulations also show that ejecta deposits strongly depend on impact angle and projectile size and, therefore, cannot be used for reliable estimates of the initial projectile mass. The initial amplitudes of tsunami-like waves are estimated. The presence of clay-rich sediments, typical for the abyssal basins in cores PS2709 and PS2708 on the Freeden Seamounts (Bellingshausen Sea, Southern Ocean) combined with numerical data allow us to suggest a probable point of impact to the east of the seamounts. The results do not exclude the possibility that a crater in the ocean bottom may exist, but such a structure has not been found yet.

Reference
Shuvalov V and Gersonde R (in press) Constraints on interpretation of the Eltanin impact from numerical simulations. Meteoritics & Planetary Science
[doi:10.1111/maps.12326]
Published by arrangement with John Wiley & Sons

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Francis Albarède¹, Emmanuelle Albalat¹ and Cin-Ty A. Lee²

¹Ecole Normale Supérieure de Lyon and CNRS, Lyon, France
²Rice University, Department of Earth Sciences, Houston, Texas, USA

The notion of a dry Moon has recently been challenged by the discovery of high water contents in lunar apatites and in melt inclusions within olivine crystals from two pyroclastic glasses. The highest and most compelling water contents were found in pyroclastic glasses that are not very common on the lunar surface. To obtain more representative constraints on the volatile content of the lunar interior, we measured the Zn content, a moderately volatile element, of mineral and rock fragments in lunar soils collected during Apollo missions. We here confirm that the Moon is significantly more depleted in Zn than the Earth. Combining Zn with existing K and Rb data on similar rocks allows us to anchor a new volatility scale based on the bond energy of nonsiderophile elements in their condensed phases. Extrapolating the volatility curve to H shows that the bulk of the lunar interior must be dry (≤1 ppm). This contrasts with the water content of the mantle sources of pyroclastic glasses, inferred to contain up to approximately 40 ppm water based on H₂O/Ce ratios. These observations are best reconciled if the pyroclastic glasses derive from localized water-rich heterogeneities in a dominantly dry lunar interior. We argue that, although late addition of 0.015% of a chondritic veneer to the Moon seems required to explain the abundance of platinum group elements (Day et al. 2007), the volatile content of the added material was clearly heterogeneous.

Reference
 F, Albalat E and Lee C-T A (in press) An intrinsic volatility scale relevant to the Earth and Moon and the status of water in the Moon. Meteoritics & Planetary Science
[doi:10.1111/maps.12331]
Published by arrangement with John Wiley & Sons

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T. Öhman^1,2,3, G. Y. Kramer^1,2 and D. A. Kring^1,2

¹Lunar and Planetary Institute, Universities Space Research Association, Houston, Texas, USA
²Center for Lunar Science and Exploration, NASA Lunar Science Institute
³Now at Arctic Planetary Science Institute, Rovaniemi, Finland

We used Moon Mineralogy Mapper (M³), Arecibo and Mini-RF radar, and Diviner radiometer data with Lunar Reconnaissance Orbiter (LRO) Camera and Kaguya Terrain Camera images to characterize the target, ejecta, and impact melt-rich lithologies in and around lunar central peak crater Kepler. M³ data indicate the impact melt rocks of crater floor to be high-Ca pyroxene dominated, distinct from the low-Ca pyroxene-dominated crater wall. The central uplift is high-Ca pyroxene dominated, and has higher albedo. These observations are consistent with thin mare basalts underlain by noritic Imbrium ejecta, underlain by gabbroic crustal material. M³ data reveal an enigmatic, splash-like feature of melt-rich material on the southeastern (uprange) crater wall and flank. M³ data also highlight halos around Kepler. In detail the halos are slightly variable, but in broad terms they define a consistent feature, offset to the inferred downrange direction, and interpreted to reflect the distribution of glass-bearing impact breccia. The radar data sets show most of the proximal ejecta to be radar-bright. However, Diviner rock abundance data do not indicate the presence of blocks on the surface nor can they be seen using LRO Narrow Angle Camera images. Thus, the blocks giving rise to the enhanced radar signal are buried. Beyond the radar-bright zone, a subtle radar-dark halo emerges, coincident with a region of very low rock abundance in Diviner data. This multidisciplinary approach provides a robust analysis of the main characteristics of a lunar complex crater and reveals previously unidentified features related to the distribution of impact melt.

Reference
Öhman T, Kramer GY and Kring DA (in press) Characterization of melt and ejecta deposits of Kepler crater from remote sensing data. Journal of Geophysical Research: Planets
[doi:10.1002/2013JE004501]
Published by arrangement with John Wiley & Sons

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Wei Wang¹ and Zhuo Li^2,3

¹National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012, China
²Department of Astronomy and Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871, China
³Key Laboratory for the Structure and Evolution of Celestial Objects, Chinese Academy of Sciences, Kunming 650011, China

A deep hard X-ray survey of the International Gamma-Ray Astrophysics Laboratory (INTEGRAL) satellite has detected for the first time non-thermal emission up to 90 keV in the Tycho supernova (SN) remnant. Its 3–100 keV spectrum is fitted with a thermal bremsstrahlung of kT ~ 0.81 ± 0.45 keV plus a power-law model of Γ ~ 3.01 ± 0.16. Based on diffusive shock acceleration theory, this non-thermal emission, together with radio measurements, implies that the Tycho remnant may not accelerate protons up to >PeV but to hundreds TeV. Only heavier nuclei may be accelerated to the cosmic ray spectral “knee.” In addition, using INTEGRAL, we search for soft gamma-ray lines at 67.9 and 78.4 keV that come from the decay of radioactive ⁴⁴Ti in the Tycho remnant. A bump feature in the 60–90 keV energy band, potentially associated with the ⁴⁴Ti line emission, is found with a marginal significance level of ~2.6σ. The corresponding 3σ upper limit on the ⁴⁴Ti line flux amounts to 1.5 × 10^-5 photon cm^-2 s^-1. Implications on the progenitor of the Tycho SN, considered to be a Type Ia SN prototype, are discussed.

Reference
Wang W and Li Z (2014) Hard X-ray emission and 44Ti line features of the Tyco supernova remnant . The Astrophysical Journal 189:123.
[doi:10.1088/0004-637X/789/2/123]

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Noguchi, T¹ et al. (>10)*
*Find the extensive, full author and affiliation list on the publishers website.

¹Faculty of Arts and Science, Kyushu University, Nishi-ku, Fukuoka, Japan

We observed cross sectional ultra-thin sections near the surface of 12 particles recovered from the S-type asteroid Itokawa by the Hayabusa spacecraft in 2010, using spherical aberration–corrected STEM and conventional TEM. Although their mineralogy is almost identical to the equilibrated LL chondrites and therefore basically anhydrous, micrometer-to-submicrometer-sized sylvite was identified on the surface of Itokawa particle RA-QD02-0034. Separately, micrometer-sized halite was also identified on the surface of Itokawa particle RA-QD02-0129. Detailed inspection of the sample processing procedures at the JAXA’s Planetary Materials Sample Curation Facility and textural observation of the sylvite and halite indicate that they were clearly present on two Itokawa particles before they were removed from Clean Chamber #2 at JAXA. However, there is no direct evidence for their extraterrestrial origin at present. If the sylvite and halite are extraterrestrial, their presence suggests that they may be more abundant on the surface of S-type asteroids than previously thought.

Reference
Noguchi et al. (in press) Sylvite and halite on particles recovered from 25143 Itokawa: A preliminary report. Meteoritics & Planetary Science
[doi:10.1111/maps.12333]
Published by arrangement with John Wiley & Sons

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