P. Beck^a,*, A. Garenne^a, E. Quirico^a, L. Bonal^a, G. Montes-Hernandez^b, F. Moynier^c, B. Schmitt^a

^aUJF-Grenoble 1 / CNRS-INSU, Institut de Planétologie et d’Astrophysique de Grenoble (IPAG) UMR 5274, Grenoble, F-38041, France
^bUJF-Grenoble 1 / CNRS-INSU, Institut des Sciences de la Terre (IsTERRE) UMR 5275, Grenoble, F-38041, France
^cDepartment of Earth and Planetary Sciences, Washington University in St Louis

In this work, infrared transmission spectra (2-25 μm range, 5000-400 cm^-1) of 40 carbonacous chondrites were analyzed (21 CMs, 5 CVs, 6 CRs, 3 CKs, 3 C2s and 2 CIs). All these meteorite groups are known to have experienced significant aqueous alteration (except the CKs). These IR measurements provide information about the parent body processes experienced, as well as spectra for comparison with observations of Solar System small bodies and possibly with astronomical observations of accretion and debris disks.
This study reveals that each meteorite group appears to have specific signatures in the measured IR spectral range measured. In the case of the CI and CM groups, results show a variability in the shape of the silicate features that can be related to the evolution of the mineralogy with increasing extent of aqueous alteration extent as described by several authors with other techniques. This evolution of the silicate feature can be seen in the variation in the relative intensities of olivine and phyllosilicate IR features. The variability in the silicate features is correlated with the intensity of an –OH related absorption at 3-μm, which can be used for the classification of the meteorites according to the level of hydration. Interestingly, in the case of CM chondrites, for which the mineralogy is expected to be dominated by phyllosilicates (serpentine mostly), the shape of the silicate absorption ressembles that of an amorphous silicate, with a broad and symmetric 10-μm band, unlike terrestrial phyllosilicates.
The CV and CK groups have IR spectra that are dominated by olivine absorption. From this feature, it is possible to determine average Mg numbers for the olivine. For the CVs, the olivine Mg numbers appear to decrease in the order Kaba-Grosnaja-Vigarano-Mokoia-Allende. This trend is likely related to the long duration of metamorphism experienced by these samples and the chemical re-equilibration between chondritic components. In the case of CK chondrites, the inferred bulk Mg# of olivine is 67 (+/- 1), and no variation is observed between the three studied samples, which is likely related to their high degree of equilibration.
The 6 CR chondrites show the most variability in their IR spectra, from CM-like spectra in the case of the CR1 Grosvenor Moutains (GRO) 95577 to CV-like spectra for Roberts Massif (RBT) 04133 and Graves Nunataks (GRA) 06100 (one of them being most probably misclassified). Spectra of the remaining CRs show mixtures of various silicate component.
Finally, these spectra can be used for comparison with emission spectra of fine-grained asteroid surfaces and dust-rich cometary tails. In the case of Tempel 1, the only group of CC that matches the observed feature around 10-μm region is the CR group. The spectral comparison shows some striking similarities between CRs and Tempel 1 dust. A genetic link between CR2 and comets is not proven, but mineralogical similarities are suggested from the IR spectra.

Reference
Beck P, Garenne A, Quirico E, Bonal L, Montes-Hernandez G, Moynier F and Schmitt B (in press) Transmission infrared spectra (2-25 microns) of carbonaceous chondrites (CI, CM, CV-CK, CR, C2 ungrouped): mineralogy, water, and asteroidal processes. Icarus
[doi:10.1016/j.icarus.2013.10.019]
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Evelyn Füri^*, Etienne Deloule, Andrey Gurenko and Bernard Marty

Centre de Recherches Pétrographiques et Géochimiques, 15 rue Notre-Dame des Pauvres, BP20, 54501 Vandoeuvre-lès-Nancy Cedex, France

In order to assess the proportion of solar, cosmogenic, and indigenous water (hydrogen) trapped in individual Ti-rich lunar volcanic glasses (LVGs) from the 74002 core obtained during the Apollo 17 mission, we coupled ion microprobe measurements of water abundances and D/H ratios with CO₂ laser extraction-static mass spectrometry analyses of noble gases (He, Ne, Ar). The large (∼300-400 μm in diameter) LVGs studied here contain a small amount of solar wind (SW) volatiles implanted at the grain surfaces, as indicated by the small concentrations of solar helium and neon that represent ⩽5% of the respective total noble gas abundances. The large proportion of volume-correlated cosmogenic gases reflects an exposure duration of ∼28 Ma, on average, of the glasses at the lunar surface. Hydrogen abundances determined in the grain interiors of glassy and partially-crystalline LVGs are equivalent to between 6.5 and 54.3 ppm H₂O. Based on the noble gas exposure ages, the correction of the measured hydrogen isotope composition for in-situ production of cosmogenic deuterium by spallation reactions varies between -5 to -254 ‰ for the different grains. Corrected δD values range from +38 ‰ to +809 ‰ in the LVGs and are anti-correlated with the water content, consistent with extensive hydrogen isotope fractionation during kinetic H₂ loss from a lunar melt with an inferred initial isotope signature of the order of -100 ‰ and a water content of 100-300 ppm. The detection of water in these primitive lunar melts confirms the presence of a non-anhydrous mantle reservoir within the Moon. Furthermore, our results reveal that the hydrogen isotope composition of water in the melt source of the 74002 LVGs is similar to that of carbonaceous chondrites. These observations indicate that the contribution of deuterium-enriched cometary water to the Earth-Moon system is negligible.

Reference
Füri E, Deloule E, Gurenko A and Marty B (in press) New evidence for chondritic lunar water from combined D/H and noble gas analyses of single Apollo 17 volcanic glasses. Icarus
[doi:10.1016/j.icarus.2013.10.029]
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M. de Val-Borro^1,2, M. Küppers³, P. Hartogh¹, L. Rezac¹, N. Biver⁴, D. Bockelée-Morvan⁴, J. Crovisier⁴, C. Jarchow¹ and G. L. Villanueva^5,6

¹Max Planck Institute for solar system Research, Max-Planck-Str. 2, 37191 Katlenburg-Lindau, Germany
²Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA
³Rosetta Science Operations Centre, European Space Astronomy Centre, European Space Agency, PO Box 78, 28691 Villanueva de la Cañada, Madrid, Spain
⁴LESIA, Observatoire de Paris, CNRS, UPMC, Université Paris-Diderot, 5 place Jules Janssen, 92195 Meudon, France
⁵solar system Exploration Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
⁶Department of Physics, Catholic University of America, Washington, DC 20064, USA

Context. The chemical composition of comets can be inferred using spectroscopic observations in submillimeter and radio wavelengths.
Aims. We aim to compare the production rates ratio of several volatiles in two comets, C/2001 Q4 (NEAT) and C/2002 T7 (LINEAR), which are generally regarded as dynamically new and likely to originate in the Oort cloud. This type of comets is considered to be composed of primitive material that has not undergone considerable thermal processing.
Methods. The line emission in the coma was measured in the comets, C/2001 Q4 (NEAT) and C/2002 T7 (LINEAR), that were observed on five consecutive nights, 7–11 May 2004, at heliocentric distances of 1.0 and 0.7 AU, respectively, by means of high-resolution spectroscopy using the 10-m Submillimeter Telescope at the Arizona Radio Observatory. Both objects became very bright and reached naked-eye visibility during their perihelion passage in the spring of 2004.
Results. We present a search for six parent- and product-volatile species (HCN, H₂CO, CO, CS, CH₃OH, and HNC) in both comets. Multiline observations of the CH₃OH J = 5−4 series allow us to estimate the rotational temperature using the rotation diagram technique. We derive rotational temperatures of 54(9) K for C/2001 Q4 (NEAT) and 119(34) K for C/2002 T7 (LINEAR). The gas production rates are computed using the level distribution obtained with a spherically symmetric molecular excitation code that includes collisions between neutrals and electrons. The effects of radiative pumping of the fundamental vibrational levels by infrared photons from the Sun are considered for the case of HCN. We find an HCN production rate of 2.96(5) × 1026 molec.s^-1 for comet C/2001 Q4 (NEAT), corresponding to a mixing ratio with respect to H₂O of 1.12(2) × 10^-3. The mean HCN production rate during the observing period is 4.54(10) × 10²⁶ molec.s^-1 for comet C/2002 T7 (LINEAR), which gives a mixing ratio of 1.51(3) × 10³. Relative abundances of CO, CH₃OH, H₂CO, CS, and HNC with respect to HCN are 3.05(83) × 10¹, 1.50(25) × 10¹, 1.16(27), 7.02(30) × 10^-1, and 5.75(73) × 10^-2 in comet C/2001 Q4 (NEAT) and < 4.12 × 10¹, 4.07(44) × 10¹, 4.72(73), 1.32(6), and 1.09(8) × 10^-1 in comet C/2002 T7 (LINEAR).
Conclusions. With systematically lower mixing ratios in comet C/2001 Q4 (NEAT), production rate ratios of the observed species with respect to H₂O lie within the typical ranges of dynamically new comets in both objects. We find a relatively low abundance of CO in C/2001 Q4 (NEAT) compared to the observed range in other comets based on millimeter/submillimeter observations, and a significant upper limit on the CO production in C/2002 T7 (LINEAR) is derived. Depletion of CO suggests partial evaporation from the surface layers during previous visits to the outer solar system and agrees with previous measurements of dynamically new comets. Rotational temperatures derived from CH₃OH rotational diagrams in both C/2001 Q4 (NEAT) and C/2002 T7 (LINEAR) are roughly consistent with observations of other comets at similar distances from the Sun.

Reference
de Val-Borro M, Küppers M, Hartogh P, Rezac L, Biver N, Bockelée-Morvan D, Crovisier J, Jarchow C and Villanueva GL (in press) A survey of volatile species in Oort cloud comets C/2001 Q4 (NEAT) and C/2002 T7 (LINEAR) at millimeter wavelengths. Astronomy & Astrophysics 559:A48.
[doi:10.1051/0004-6361/201322284]
Reproduced with permission © ESO

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D. P. Moriarty^1,*, C. M. Pieters¹ and P. J. Isaacson²

¹Department of Geological Sciences, Brown University, Providence, Rhode Island, USA
²HIGP, University of Hawaii, Manoa, Hawaii, USA

Using high-spectral and -spatial resolution Moon Mineralogy Mapper data, we investigate compositional variations across the central peak structures of four impact craters within the South Pole-Aitken Basin (SPA). Two distinct causes of spectral diversity are observed. Spectral variations across the central peaks of Bhabha, Finsen, and Lyman are dominated by soil development, including the effects of space weathering and mixing with local materials. For these craters, the central peak structure is homogeneous in composition, although small compositional differences between the craters are observed. This group of craters is located within the estimated transient cavity of SPA, and their central uplifts exhibit similar mafic abundances. Therefore, it is plausible that they have all uplifted material associated with melts of the lower crust or upper mantle produced during the SPA impact. Compositional differences observed between the peaks of these craters reflect heterogeneities in the SPA subsurface, although the origin of this heterogeneity is uncertain. In contrast to these craters, Leeuwenhoek exhibits compositional heterogeneity across its central peak structure. The peak is areally dominated by feldspathic materials, interspersed with several smaller exposures exhibiting a mafic spectral signature. Leeuwenhoek is the largest crater included in the study and is located in a region of complex stratigraphy involving both crustal (feldspathic) and SPA (mafic melt and ejecta) materials. The compositional diversity observed in Leeuwenhoek’s central peak indicates that kilometer-scale heterogeneities persist to depths of more than 10 km in this region.

Reference
Moriarty DP, Pieters CM and Isaacson PJ (in press) Compositional heterogeneity of central peaks within the South Pole-Aitken Basin. Journal of Geophysical Research – Planets
[doi:10.1002/2013JE004376]
Published by arrangement with John Wiley & Sons

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Zou Xiaoduan^a,b, Li Chunlai^a,*, Liu Jianjun^a, Wang Wenrui^a, Li Han^a, Ping Jinsong^a

^aKey Laboratory of Lunar and Deep Space Exploration, National Astronomical Observatories, Chinese Academy of Sciences, A20 Datun Road, Chaoyang, Beijing 100012, China
^bUniversity of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, China

On 2012 December, 13, 08:30 (UTC), Chang’E-2 flew by asteroid 4179 Toutatis in deep space seven million kilometers away from Earth. The flyby mission returned clear optical images of Toutatis for the first time. The flyby distance and image pixel scale were calculated from the image size of the asteroid compared to a predicted view of an earlier radar shape model. We compared the similarities and differences in both the radar model and the CE-2 photo mosaic, and measured the craters and lumps on the surface of Toutatis. We preliminarily analyzed the topography of the Toutatis surface. We found that the density of craters on the small lobe is less than that on the big lobe.

Reference
Xiaoduan Z, Chunlai L, Jianjun L, Wenrui W, Han L and Jinsong P (in press) The Preliminary Analysis of the 4179 Toutatis Snapshots of the Chang’E-2 Flyby. Icarus
[doi:10.1016/j.icarus.2013.11.002]
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