¹Motoo Ito et al. (>10)*
¹Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science Technology (JAMSTEC), Nankoku, Kochi 783-8502, Japan
*Find the extensive, full author and affiliation list on the publishers Website

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

Reference
Ito M et al. (2014) H, C, and N isotopic compositions of Hayabusa category 3 organic samples. Earth, Planets and Space  66, 91
Link to Article [doi:10.1186/1880-5981-66-91]

¹Michelle S Thompson, ²Roy Christoffersen, ¹Thomas J Zega, ³Lindsay P Keller
¹ Lunar and Planetary Laboratory, University of Arizona, 1629 E University Blvd, Tucson, AZ 85721, USA
²Jacobs, NASA Johnson Space Center, Mail Code KR, Houston, TX 77058,USA
³NASA JSC Mail Code KR, Houston, TX 77058, USA

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

Reference
Thompson MS, Christofferson R, Zega TJ, Keller LP (2014) Microchemical and structural evidence for space weathering in soils from asteroid Itokawa. Earth, Planets and Space 66, 89
Link to Article [doi:10.1186/1880-5981-66-89]

¹Micah J. Schaible, ¹Raúl A. Baragiola
¹Laboratory of Atomic and Surface Physics, University of Virginia, Charlottesville, VA

Hydroxyl on the lunar surface revealed by remote measurements has been thought to originate from solar wind hydrogen implantation in the regolith. The hypothesis is tested here through experimental studies of the rate and mechanisms of OH bond formation due to H+ implantation of amorphous SiO2 and olivine in ultrahigh vacuum. The samples were implanted with 2–10 keV H+, in the range of solar wind energies and the OH absorption band at ~2.8 µm measured by transmission FTIR spectroscopy. For 2 keV protons in SiO2, the OH band depth saturated at fluences F ~5 × 1016 H+/cm2 to a maximum 0.0032 absorption band depth, corresponding to a column density ηs = 1.1 × 1016 OH/cm2. The corresponding values for 5 keV protons in olivine are > 2 × 1017/cm2, 0.0067 and 4.0 × 1016 OH/cm2. The initial conversion rate of implanted H+ into hydroxyl species was found to be ~90% and decreased exponentially with fluence. There was no evidence for molecular water formation due to proton irradiation. Translating the laboratory measurements in thin plate samples to the granular lunar regolith, it is estimated that the measurements can account for a maximum of 17% relative OH absorption in reflectance spectroscopy of mature soils, consistent with spacecraft observations in the infrared of the Moon.

Reference
Schaible MJ, Baragiola RA (2014) The role of solar wind in SiOH bond formation on the surfaces of airless bodies in space. Journal of Geophysical Research: Planets (in Press)
Link to Article [DOI: 10.1002/2014JE004650]

Published by arrangement with John Wiley & Sons

^1,6Kereszturi, A., ²Blumberger, Z., ³Józsa, S., ⁴May, Z., ⁵Müller, A., ⁵Szabó, M. ⁵Tóth, M.
¹Research Center for Astronomy and Earth Sciences, Konkoly Thege Miklós Astronomical Institute, Astrophysical and Geochemical Laboratory, Hungarian Academy of Sciences, Budapest, Hungary
²Eotvos Lorand University of Sciences, Faculty of Science, Centre of Environmental Sciences, Hungarian Academy of Sciences, Budapest, Hungary
³Faculty of Science, Department of Petrology and Geochemistry, Eotvos Lorand University of Sciences, Hungarian Academy of Sciences, Budapest, Hungary
⁴Institute of Materials and Environmental Chemistry, Chemical Research Center, Hungarian Academy of Sciences, Budapest, Hungary
⁵Research Center for Astronomy and Earth Sciences, Institute for Geological and Geochemical Research, Hungarian Academy of Sciences, Budapest, Hungary
⁶NASA Astrobiology Institute; Thermodynamics, Disequilibrium and Evolution Focus Group

Analysis of the NWA 2086 CV3 chondrite showed a matrix/chondrule ratio of 52%, similar to Bali, Mokoia, and Grosanaja. Nearly twice as many chondrule fragments as intact ones demonstrate that an early fragmentation phase occurred prior to final accretion. After this event, no substantial mechanical change or redeposition is evident. Rims with double-layered structures were identified around some chondrules, which, in at least one case, is attributed to an accretionary origin. The rim’s outer parts with a diffuse appearance were formed by in situ chemical alteration. During this later process, Mg content decreased, Fe content increased, and olivine composition was homogenized, producing a rim composition close to that of the matrix. This alteration occasionally happened along fractures and at confined locations, and was probably produced by fluid interactions. Iron oxides are the best candidate for a small grain-sized alteration product; however, technical limitations in the available equipment did not allow exact phase identification. These results suggest that NWA 2086 came from a location (possible more deeply buried) in the CV parent body than Mokoia or Bali, and suffered less impact effects—although there is no evidence of sustained thermal alteration. This meteorite may represent a sample of the CV parent asteroid interior and provide a useful basis for comparison with other CV meteorites in the future.

Reference
Kereszturi A, Blumberger Z, Józsa S, May Z, Müller A, Szabó M, Tóth M (2014) Alteration processes in the CV chondrite parent body based on analysis of NWA 2086 meteorite. Meteoritics & Planetary Science (in Press).
Link to Article [doi: 10.1111/maps.12336]

Published by arrangement with John Wiley & Sons