John W. Valley, Michael J. Spicuzza and Takayuki Ushikubo

WiscSIMS, Department of Geoscience, University of Wisconsin, 1215 W. Dayton St., Madison, WI, 53706, USA

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Reference
Valley JW, Spicuzza MJ and Ushikubo T (2014) Correlated δ18O and [Ti] in lunar zircons: a terrestrial perspective for magma temperatures and water content on the Moon. Contributions to Mineralogy and Petrology 167:956.
[doi:10.1007/s00410-013-0956-4]

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Hiroshi Kimura

Graduate School of Science, Kobe University, c/o CPS (Center for Planetary Science), Chuo-ku Minatojima Minamimachi
7-1-48, Kobe 650-0047, Japan

We model dust in comets, protoplanetary disks, and debris disks as aggregates consisting of submicron-sized grains with a silicate core and an organic-rich carbonaceous mantle. By computing the infrared (IR) spectra of the aggregates, we show that the degree of carbonization determines the positions of infrared peaks characteristic of magnesium-rich crystalline silicates. We discuss our results in terms of processing of organic materials by ultraviolet irradiation, ion bombardments, and thermal devolatilization. A comparison between the model IR spectra of the aggregates and the observed spectra of dust in circumstellar disks reveals that at least one third of the organic refractory component has suffered from carbonization in a very short timescale.

Reference
Kimura H (in press) The Organic-Rich Carbonaceous Component of Dust Aggregates in Circumstellar Disks: Effects of Its Carbonization on Infrared Spectral Features of Its Magnesium-Rich Olivine Counterpart. Icarus
[doi:10.1016/j.icarus.2014.01.009]
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Romain Tartèse^a and Mahesh Anand^b

^aPlanetary and Space Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6AA, United Kingdom
^bDepartment of Earth Sciences, The Natural History Museum, Cromwell Road, London, SW7 5BD, United Kingdom

Referes to
Romain Tartèse, Mahesh Anand
Late delivery of chondritic hydrogen into the lunar mantle: Insights from mare basalts
Earth and Planetary Science Letters, Volume 361, 1 January 2013, Pages 480-486

The authors regret for an error which was introduced in an intermediate step involved in calculating the amount of chondritic material added to the lunar interior to account for the estimated H content of the mare basalt source regions (Section 6, lines 12–25). The revised text is as follows:
Assuming a 400 km deep solidified mantle with 25 ppm H and a density of 3300 kg m⁻³ implies that∼1×10¹⁸ kg of H has been added by chondrite-type impactors and efficiently mixed in the upper lunar mantle. Taking the measured H content of ∼5000–15 000 ppm in CI chondrites (Alexander et al., 2012 and Kerridge, 1985), this represents a mass of about 6.2×10¹⁹ to 1.8×10²⁰ kg of CI-type material accreted to the lunar upper mantle. This corresponds to 0.2–0.5 wt.% of the 400 km deep upper mantle considered here. By comparison, HSE abundances in lunar basalts require an amount of ∼1.6×10¹⁹ kgof chondritic material to have been accreted and mixed into the lunar upper mantle (Bottke et al., 2010 and Day et al., 2007), around 8±4 times less than that required for a lunar mantle with 25 ppm H.

Reference
Tartèse R and Anand M (in press) Corrigendum to “Late delivery of chondritic hydrogen into the lunar mantle: Insights from mare basalts” [Earth Planet. Sci. Lett. 361 (2013) 480–486]. Earth and Planetary Science Letters
[doi:10.1016/j.epsl.2014.01.002]
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Sachiko Amari^a, Ernst Zinner^a, Roberto Gallino^b

^aMcDonnell Center for the Space Sciences and the Physics Department, Washington University, St. Louis, MO 63130, USA
^bDipartimento di Fisica, Università di Torino, I-10125 Torino, Italy

We studied presolar graphite grains from four density fractions, KE3 (1.65 – 1.72 g/cm³), KFA1 (2.05 – 2.10 g/cm³), KFB1 (2.10 – 2.15 g/cm³), and KFC1 (2.15 – 2.20 g/cm³), extracted from the Murchison (CM2) meteorite, with the ion microprobe. One of the most interesting features of presolar graphite is that isotopic features depend on density. There are grains with ¹⁵N and ¹⁸O excesses, Si isotopic anomalies, high ²⁶Al/²⁷Al ratios (∼ 0.1), and Ca and Ti isotopic anomalies, including the initial presence of short-lived ⁴¹Ca and ⁴⁴Ti. These isotopic features are qualitatively explained by nucleosynthesis in core collapse supernovae. We estimate that 76%, 50%, 7% and 1% of the KE3, KFA1, KFB1 and KFC1 grains, respectively, are supernova grains. We performed 3- and 4-zone supernova mixing calculations to reproduce the C, O (¹⁸O/¹⁶O) and Al isotopic ratios of the KE3 grains, using 15M_⊙ model calculations by Rauscher et al. (2002). Isotopic ratios of grains with high ¹²C/¹³C ratios (> 200) can be reproduced, whereas those of grains with ratios ⩽ 200 are hard to explain if we assume that graphite grains form in C-rich conditions.
We compared the distributions of the ¹²C/¹³C ratios of KFB1 and KFC1 grains and their s-process ⁸⁶Kr/⁸²Kr ratios inferred from bulk noble gas analysis to model calculations of asymptotic giant branch (AGB) stars with a range of mass and metallicity. We conclude that KFB1 grains with ¹²C/¹³C > 100 formed in the outflow of low-mass (1.5, 2 and 3M_⊙) low-metallicity (Z = 3 × 10^–3 for 1.5, 2 and 3M_⊙, Z = 6 × 10^–3 for 3M_⊙ only) AGB stars and that KFC1 grains with ¹²C/¹³C > 60 formed in those stars as well as in 5M_⊙ stars of solar and/or half-solar metallicities. Grains with ¹²C/¹³C < 20 in all the fractions seem to have multiple origins. Some of them formed in the ejecta of core-collapse supernovae. J stars and born-again AGB stars are also possible stellar sources.
We calculated the abundances of graphite grains from supernovae and AGB stars in the Murchison meteorite to be 0.24 ppm and 0.44 ppm, respectively, whereas those of SiC grains from supernovae and AGB stars are 0.065 ppm and 5.7 ppm, respectively. In contrast to graphite, AGB stars are a dominant source of SiC grains.
Since different mineral types have different residence times in the interstellar medium, their abundances in meteorites may not reflect original yields in stellar sources. Silicon carbide is mechanically more resistant than graphite and we assume that residence times of SiC are longer than those of graphite. Silicon carbide grains from AGB stars are much more abundant than graphite grains from AGB stars (5.7 ppm vs. 0.44 ppm). We speculate that one of the reasons that SiC grains from AGB stars are much more abundant than graphite grains from AGB stars is that major sources for graphite grains are 3 M_⊙ stars whereas for SiC lower-mass (1.5 – 2M_⊙) stars; lower-mass stars are more abundant. The abundances of supernova graphite grains and supernova SiC grains (0.24 ppm vs. 0.065 ppm) reflect grain formation and destruction in expanding supernova ejecta.

Reference
Amari S, Zinner E and Gallino R (in press) Isotopic study of presolar graphite from the murchison meteorite. Geochimica et Cosmochimica Acta
[doi:10.1016/j.gca.2014.01.006]
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Ertel S et al.¹ (>10)*
*Find the extensive, full author and affiliation list on the publishers website.

¹UJF-Grenoble 1/CNRS-INSU, Institut de Planétologie et d’Astrophysique de Grenoble (IPAG) UMR 5274, 38041 Grenoble, France

Context. The dust observed in debris disks is produced through collisions of larger bodies left over from the planet/planetesimal formation process. Spatially resolving these disks permits to constrain their architecture and thus that of the underlying planetary/planetesimal system.
Aims. Our Herschel open time key program DUNES aims at detecting and characterizing debris disks around nearby, sun-like stars. In addition to the statistical analysis of the data, the detailed study of single objects through spatially resolving the disk and detailed modeling of the data is a main goal of the project.
Methods. We obtained the first observations spatially resolving the debris disk around the sun-like star HIP 17439 (HD 23484) using the instruments PACS and SPIRE on board the Herschel Space Observatory. Simultaneous multi-wavelength modeling of these data together with ancillary data from the literature is presented.
Results. A standard single component disk model fails to reproduce the major axis radial profiles at 70  μm, 100  μm, and 160  μm simultaneously. Moreover, the best-fit parameters derived from such a model suggest a very broad disk extending from few au up to few hundreds of au from the star with a nearly constant surface density which seems physically unlikely. However, the constraints from both the data and our limited theoretical investigation are not strong enough to completely rule out this model. An alternative, more plausible, and better fitting model of the system consists of two rings of dust at approx. 30 au and 90 au, respectively, while the constraints on the parameters of this model are weak due to its complexity and intrinsic degeneracies.
Conclusions. The disk is probably composed of at least two components with different spatial locations (but not necessarily detached), while a single, broad disk is possible, but less likely. The two spatially well-separated rings of dust in our best-fit model suggest the presence of at least one high mass planet or several low-mass planets clearing the region between the two rings from planetesimals and dust.

Reference
Ertel S et al. (in press) Potential multi-component structure of the debris disk around HIP 17439 revealed by Herschel/DUNES. Astronomy & Astrophysics 561:A114.
[doi:10.1051/0004-6361/201219945]
Reproduced with permission © ESO

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Cartier Camille^a,b,c, Hammouda Tahar^a,b,c, Doucelance Régis^a,b,c, Boyet Maud^a,b,c, Devidal Jean-Luc^a,b,c, Moine Bertrand^b,c,d

^aClermont Université, Université Blaise Pascal, Laboratoire Magmas et Volcans, BP 10448, F-63000 Clermont-Ferrand, France
^bCNRS, UMR 6524, LMV, F-63038 Clermont-Ferrand, France
^cIRD, R 163, LMV, F-63038 Clermont-Ferrand, France
^dDépartement de Géologie, Université Jean Monnet, 23 rue du Dr P. Michelon, 42023 Saint-Etienne, Cedex 02, France

In order to investigate the influence of very reducing conditions, we report enstatite-melt trace element partition coefficients (D) obtained on enstatite chondrite material at 5 GPa and under oxygen fugacities (fO₂) ranging between 0.8 and 8.2 log units below the iron-wustite (IW) buffer. Experiments were conducted in a multianvil apparatus between 1580 and 1850°C, using doped (Sc, V, REE, HFSE, U, Th) starting materials. We used a two-site lattice strain model and a Monte-Carlo-type approach to model experimentally determined partition coefficient data. The model can fit our partitioning data i.e. trace elements repartition in enstatite, which provides evidence for the attainment of equilibrium in our experiments. The precision on the lattice strain model parameters obtained from modelling does not enable determination of the influence of intensive parameters on crystal chemical partitioning, within our range of conditions (fO₂, P, T, composition). We document the effect of variable oxygen fugacity on the partitioning of multivalent elements. Cr and V, which are trivalent in the pyroxene at around IW-1 are reduced to 2+ state with increasingly reducing conditions, thus affecting their partition coefficients. In our range of redox conditions Ti is always present as a mixture between 4+ and 3+ states. However the Ti³⁺/Ti⁴⁺ ratio increases strongly with increasingly reducing conditions. Moreover in highly reducing conditions, Nb and Ta, that usually are pentavalent in magmatic systems, appear to be reduced to lower valence species, which may be Nb²⁺ and Ta³⁺. We propose a new proxy for fO₂ based on D(Cr)/D(V) ratio. Our new data extend the redox range covered by previous studies and allows this proxy to be used in the whole range of redox conditions of the solar system objects. We selected trace-element literature data of six chondrules on the criterion of their equilibrium. Applying the proxy to opx-matrix systems, we estimated that three type I chondrules have equilibrated at IW-7±1, one type I chondrule at IW-4±1, and two type II chondrules at IW+3±1. This first accurate estimation of enstatite-melt fo₂for type I chondrules is very close to CAI values.

Reference
Camille C, Tahar H, Régis D, Maud B, Jean-Luc D, Bertrand M (in press) Experimental study of trace element partitioning between enstatite and melt in Enstatite-Chondrites at low oxygen fugacities and 5 GPa. Geochimica et Cosmochimica Acta
[doi:10.1016/j.gca.2014.01.002]
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Hiroshi Kimura

Graduate School of Science, Kobe University, c/o CPS (Center for Planetary Science), Chuo-ku Minatojima Minamimachi 7-1-48, Kobe 650-0047, Japan

We model dust in comets, protoplanetary disks, and debris disks as aggregates consisting of submicron-sized grains with a silicate core and an organic-rich carbonaceous mantle. By computing the infrared (IR) spectra of the aggregates, we show that the degree of carbonization determines the positions of infrared peaks characteristic of magnesium-rich crystalline silicates. We discuss our results in terms of processing of organic materials by ultraviolet irradiation, ion bombardments, and thermal devolatilization. A comparison between the model IR spectra of the aggregates and the observed spectra of dust in circumstellar disks reveals that at least one third of the organic refractory component has suffered from carbonization in a very short timescale.

Reference
Kimura H (in press) The Organic-Rich Carbonaceous Component of Dust Aggregates in Circumstellar Disks: Effects of Its Carbonization on Infrared Spectral Features of Its Magnesium-Rich Olivine Counterpart. Icarus
[doi:10.1016/j.icarus.2014.01.009]
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F. Moreno¹, J. Licandro^2,3, C. Álvarez-Iglesias^2,3,4, A. Cabrera-Lavers^2,3,4 and F. Pozuelos¹

¹Instituto de Astrofísica de Andalucía, CSIC, Glorieta de la Astronomía s/n, E-18008 Granada, Spain
²Instituto de Astrofísica de Canarias, c/Vía Láctea s/n, E-38200 La Laguna, Tenerife, Spain
³Departamento de Astrofísica, Universidad de La Laguna (ULL), E-38205 La Laguna, Tenerife, Spain
⁴GTC Project, E-38205 La Laguna, Tenerife, Spain

We present observations and models of the dust environment of activated asteroid P/2013 P5 (PANSTARRS). The object displayed a complex morphology during the observations, with the presence of multiple tails. We combined our own observations, all made with instrumentation attached to the 10.4 m Gran Telescopio Canarias on La Palma, with previously published Hubble Space Telescopeimages to build a model aimed at fitting all the observations. Altogether, the data cover a full three month period of observations which can be explained by intermittent dust loss. The most plausible scenario is that of an asteroid rotating with the spinning axis oriented perpendicular to the orbit plane and losing mass from the equatorial region, consistent with rotational break-up. Assuming that the ejection velocity of the particles (v ~0.02–0.05 m s^-1) corresponds to the escape velocity, the object diameter is constrained to ~30–130 m for bulk densities 3000–1000 kg m^-3.

Reference
Moreno F, Licandro J, Álvarez-Iglesias C, Cabrera-Lavers A and Pozuelos F (2014) Intermittent Dust Mass Loss from Activated Asteroid P/2013 P5 (PANSTARRS). The Astrophysical Journal 781:118.
[doi:10.1088/0004-637X/781/2/118]

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M. E. Schmidt¹ et al. (>10)*
*Find the extensive, full author and affiliation list on the publishers website.

¹Department of Earth Sciences, Brock University, St. Catharines, Ontario, Canada

The first four rocks examined by the Mars Science Laboratory Alpha Particle X-ray Spectrometer indicate that Curiosity landed in a lithologically diverse region of Mars. These rocks, collectively dubbed the Bradbury assemblage, were studied along an eastward traverse (sols 46–102). Compositions range from Na- and Al-rich mugearite Jake_Matijevic to Fe-, Mg-, and Zn-rich alkali-rich basalt/hawaiite Bathurst_Inlet and span nearly the entire range in FeO* and MnO of the data sets from previous Martian missions and Martian meteorites. The Bradbury assemblage is also enriched in K and moderately volatile metals (Zn and Ge). These elements do not correlate with Cl or S, suggesting that they are associated with the rocks themselves and not with salt-rich coatings. Three out of the four Bradbury rocks plot along a line in elemental variation diagrams, suggesting mixing between Al-rich and Fe-rich components. ChemCam analyses give insight to their degree of chemical heterogeneity and grain size. Variations in trace elements detected by ChemCam suggest chemical weathering (Li) and concentration in mineral phases (e.g., Rb and Sr in feldspars). We interpret the Bradbury assemblage to be broadly volcanic and/or volcaniclastic, derived either from near the Gale crater rim and transported by the Peace Vallis fan network, or from a local volcanic source within Gale Crater. High Fe and Fe/Mn in Et_Then likely reflect secondary precipitation of Fe³⁺ oxides as a cement or rind. The K-rich signature of the Bradbury assemblage, if igneous in origin, may have formed by small degrees of partial melting of metasomatized mantle.

Reference
Schmidt ME et al. (in press) Geochemical diversity in first rocks examined by the Curiosity Rover in Gale Crater: Evidence for and significance of an alkali and volatile-rich igneous source. Journal of Geophysical Research: Planets
[doi:10.1002/2013JE004481]
Published by arrangement with John Wiley & Sons

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Andrew R. Poppe

Space Sciences Laboratory, 7 Gauss Way, University of California at Berkeley, Berkeley, CA, 94720, USA

The influx of interplanetary dust grains (IDPs) to the Pluto-Charon system is expected to drive several physical processes, including the formation of tenuous dusty rings and/or exospheres, the deposition of neutral material in Pluto’s atmosphere through ablation, the annealing of surface ices, and the exchange of ejecta between Pluto and its satellites. The characteristics of these physical mechanisms are dependent on the total incoming mass, velocity, variability, and composition of interplanetary dust grains; however, our knowledge of the IDP environment in the Edgeworth-Kuiper Belt has, until recently, remained rather limited. Newly-reported measurements by the New Horizons Student Dust Counter combined with previous Pioneer 10 meteoroid measurements and a dynamical IDP tracing model have improved the characterization of the IDP environment in the outer solar system, including at Pluto-Charon. Here we report on this modeling and data comparison effort, including a discussion of the IDP influx to Pluto and its moons, and the implications thereof.

Reference
Poppe AR (in press) Interplanetary dust influx to the Pluto-Charon system. Icarus
[doi:10.1016/j.icarus.2013.12.029]
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