ALBERT

Description: Bright carbonate deposits as evidence of aqueous alteration on (1) Ceres Nature 536, 7614 (2016). doi:10.1038/nature18290 Authors: M. C. De Sanctis, A. Raponi, E. Ammannito, M. Ciarniello, M. J. Toplis, H. Y. McSween, J. C. Castillo-Rogez, B. L. Ehlmann, F. G. Carrozzo, S. Marchi, F. Tosi, F. Zambon, F. Capaccioni, M. T. Capria, S. Fonte, M. Formisano, A. Frigeri, M. Giardino, A. Longobardo, G. Magni, E. Palomba, L. A. McFadden, C. M. Pieters, R. Jaumann, P. Schenk, R. Mugnuolo, C. A. Raymond & C. T. Russell The typically dark surface of the dwarf planet Ceres is punctuated by areas of much higher albedo, most prominently in the Occator crater. These small bright areas have been tentatively interpreted as containing a large amount of hydrated magnesium sulfate, in contrast to the average surface, which is a mixture of low-albedo materials and magnesium phyllosilicates, ammoniated phyllosilicates and carbonates. Here we report high spatial and spectral resolution near-infrared observations of the bright areas in the Occator crater on Ceres. Spectra of these bright areas are consistent with a large amount of sodium carbonate, constituting the most concentrated known extraterrestrial occurrence of carbonate on kilometre-wide scales in the Solar System. The carbonates are mixed with a dark component and small amounts of phyllosilicates, as well as ammonium carbonate or ammonium chloride. Some of these compounds have also been detected in the plume of Saturn’s sixth-largest moon Enceladus. The compounds are endogenous and we propose that they are the solid residue of crystallization of brines and entrained altered solids that reached the surface from below. The heat source may have been transient (triggered by impact heating). Alternatively, internal temperatures may be above the eutectic temperature of subsurface brines, in which case fluids may exist at depth on Ceres today.

Description: The dwarf planet Ceres is known to host phyllosilicate minerals at its surface, but their distribution and origin have not previously been determined. We used the spectrometer onboard the Dawn spacecraft to map their spatial distribution on the basis of diagnostic absorption features in the visible and near-infrared spectral range (0.25 to 5.0 micrometers). We found that magnesium- and ammonium-bearing minerals are ubiquitous across the surface. Variations in the strength of the absorption features are spatially correlated and indicate considerable variability in the relative abundance of the phyllosilicates, although their composition is fairly uniform. These data, along with the distinctive spectral properties of Ceres relative to other asteroids and carbonaceous meteorites, indicate that the phyllosilicates were formed endogenously by a globally widespread and extensive alteration process.

Description: Enantiopure N(Boc)-β 3 -amino nitriles, valuable synthetic intermediates in the multistep homologation of α-amino acids, were alkylated using n-BuLi as base. Alkylations afforded easily separable, almost equimolecular mixtures of diastereomeric N(Boc)-protected syn and anti β 2,3 -amino nitriles. Suitable manipulations of both cyano and amino groups eventually led to enantiopure N- and/or C-protected β 2,3 -amino acids. For example, methanolysis using conc. HCl gas in MeOH, provides C-protected β 2,3 amino acids in excellent yields. This methodology is applied to the synthesis of a series N(Boc)-β 2,3 -dialkyl amino nitriles derived from l-phenylalanine, d-phenylalanine, l-valine and one C-protected β 2,3 amino acid. We demonstrate an efficient procedure for the preparation of anti and syn β 2,3 -amino acids with alkyl side chains, from α-amino acids in reasonable yields.

Description: Abstract Thermal inertia is a key information to quantify the physical status of a planetary surface. We derive the thermal inertia of the surface of Ceres using spatially‐resolved data from the Dawn mission. For each location, this quantity can be constrained by comparing theoretical and observed diurnal temperature profiles from retrieved temperatures. We calculated Ceres’ surface theoretical temperatures with a thermophysical model that provides temperature as a function of thermal conductivity and roughness, and we determined the values of those parameters for which the best fit with the observed data is obtained. Our results suggest that the area of crater Haulani displays thermal inertia values (up to 130‐140 Jm−2 s−½ K−1) substantially higher than the very low to low values (from 1‐15 to 50‐60 Jm−2 s−½ K−1) derived for the overall surface of Ceres. The results are more ambiguous for the bright faculae located in the floor of crater Occator.

Description: Studies of the dwarf planet (1) Ceres using ground-based and orbiting telescopes have concluded that its closest meteoritic analogues are the volatile-rich CI and CM carbonaceous chondrites. Water in clay minerals, ammoniated phyllosilicates, or a mixture of Mg(OH)2 (brucite), Mg2CO3 and iron-rich serpentine have all been proposed to exist on the surface. In particular, brucite has been suggested from analysis of the mid-infrared spectrum of Ceres. But the lack of spectral data across telluric absorption bands in the wavelength region 2.5 to 2.9 micrometres--where the OH stretching vibration and the H2O bending overtone are found--has precluded definitive identifications. In addition, water vapour around Ceres has recently been reported, possibly originating from localized sources. Here we report spectra of Ceres from 0.4 to 5 micrometres acquired at distances from ~82,000 to 4,300 kilometres from the surface. Our measurements indicate widespread ammoniated phyllosilicates across the surface, but no detectable water ice. Ammonia, accreted either as organic matter or as ice, may have reacted with phyllosilicates on Ceres during differentiation. This suggests that material from the outer Solar System was incorporated into Ceres, either during its formation at great heliocentric distance or by incorporation of material transported into the main asteroid belt.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉De Sanctis, M C -- Ammannito, E -- Raponi, A -- Marchi, S -- McCord, T B -- McSween, H Y -- Capaccioni, F -- Capria, M T -- Carrozzo, F G -- Ciarniello, M -- Longobardo, A -- Tosi, F -- Fonte, S -- Formisano, M -- Frigeri, A -- Giardino, M -- Magni, G -- Palomba, E -- Turrini, D -- Zambon, F -- Combe, J-P -- Feldman, W -- Jaumann, R -- McFadden, L A -- Pieters, C M -- Prettyman, T -- Toplis, M -- Raymond, C A -- Russell, C T -- England -- Nature. 2015 Dec 10;528(7581):241-4. doi: 10.1038/nature16172.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Istituto di Astrofisica e Planetologia Spaziali, INAF, Via del Fosso del Cavaliere 100, 00133 Roma, Italy. ; Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California 90095-1567, USA. ; Southwest Research Institute, 1050 Walnut Street, Boulder, Colorado 80302, USA. ; Bear Fight Institute, 22 Fiddler's Road, PO Box 667, Winthrop, Washington 98862, USA. ; Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, Tennessee 37996-1410, USA. ; Planetary Science Institute, Tucson, Arizona 85719-2395, USA. ; Institute of Planetary Research, German Aerospace Center (DLR), Rutherfordstrasse 2, 12489 Berlin, Germany. ; NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA. ; Department of Earth, Environmental, and Planetary Sciences, Brown University, Providence, Rhode Island 02912, USA. ; Institut de Recherche d'Astrophysique et Planetologie, Observatoire Midi Pyrenees, Universite Paul Sabatier, 14 Avenue E. Belin, 31400 Toulouse, France. ; Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26659184" target="_blank"〉PubMed〈/a〉

Description: The VIRTIS (Visible, Infrared and Thermal Imaging Spectrometer) instrument on board the Rosetta spacecraft has provided evidence of carbon-bearing compounds on the nucleus of the comet 67P/Churyumov-Gerasimenko. The very low reflectance of the nucleus (normal albedo of 0.060 +/- 0.003 at 0.55 micrometers), the spectral slopes in visible and infrared ranges (5 to 25 and 1.5 to 5% kA(-1)), and the broad absorption feature in the 2.9-to-3.6-micrometer range present across the entire illuminated surface are compatible with opaque minerals associated with nonvolatile organic macromolecular materials: a complex mixture of various types of carbon-hydrogen and/or oxygen-hydrogen chemical groups, with little contribution of nitrogen-hydrogen groups. In active areas, the changes in spectral slope and absorption feature width may suggest small amounts of water-ice. However, no ice-rich patches are observed, indicating a generally dehydrated nature for the surface currently illuminated by the Sun.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Capaccioni, F -- Coradini, A -- Filacchione, G -- Erard, S -- Arnold, G -- Drossart, P -- De Sanctis, M C -- Bockelee-Morvan, D -- Capria, M T -- Tosi, F -- Leyrat, C -- Schmitt, B -- Quirico, E -- Cerroni, P -- Mennella, V -- Raponi, A -- Ciarniello, M -- McCord, T -- Moroz, L -- Palomba, E -- Ammannito, E -- Barucci, M A -- Bellucci, G -- Benkhoff, J -- Bibring, J P -- Blanco, A -- Blecka, M -- Carlson, R -- Carsenty, U -- Colangeli, L -- Combes, M -- Combi, M -- Crovisier, J -- Encrenaz, T -- Federico, C -- Fink, U -- Fonti, S -- Ip, W H -- Irwin, P -- Jaumann, R -- Kuehrt, E -- Langevin, Y -- Magni, G -- Mottola, S -- Orofino, V -- Palumbo, P -- Piccioni, G -- Schade, U -- Taylor, F -- Tiphene, D -- Tozzi, G P -- Beck, P -- Biver, N -- Bonal, L -- Combe, J-Ph -- Despan, D -- Flamini, E -- Fornasier, S -- Frigeri, A -- Grassi, D -- Gudipati, M -- Longobardo, A -- Markus, K -- Merlin, F -- Orosei, R -- Rinaldi, G -- Stephan, K -- Cartacci, M -- Cicchetti, A -- Giuppi, S -- Hello, Y -- Henry, F -- Jacquinod, S -- Noschese, R -- Peter, G -- Politi, R -- Reess, J M -- Semery, A -- New York, N.Y. -- Science. 2015 Jan 23;347(6220):aaa0628. doi: 10.1126/science.aaa0628.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Istituto di Astrofisica e Planetologia Spaziali, Istituto Nazionale di Astrofisica (INAF), Rome, Italy. fabrizio.capaccioni@iaps.inaf.it. ; Istituto di Astrofisica e Planetologia Spaziali, Istituto Nazionale di Astrofisica (INAF), Rome, Italy. ; Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique, Observatoire de Paris/CNRS/Universite Pierre et Marie Curie[acute accent over last letter in "Universite"]/Universite Paris-Diderot, Meudon, France. ; Institute for Planetary Research, Deutsches Zentrum fur Luft- und Raumfahrt (DLR), Berlin, Germany. ; Universite Grenoble Alpes, CNRS, Institut de Planetologie et d'Astrophysique de Grenoble, Grenoble, France. ; Osservatorio di Capodimonte, INAF, Napoli, Italy. ; Bear Fight Institute, Winthrop, WA 98862, USA. ; University of California, Los Angeles, Los Angeles, CA 90095, USA. ; European Space Agency (ESA), European Space Research and Technology Centre (ESTEC), Noordwijk, Netherlands. ; Institut d'Astrophysique Spatial, CNRS, Orsay, France. ; Dipartimento di Matematica e Fisica "Ennio De Giorgi," Universita del Salento, Italy. ; Space Research Centre, Polish Academy of Sciences, Warsaw, Poland. ; NASA Jet Propulsion Laboratory, Pasadena, CA 91109, USA. ; Space Physics Research Laboratory, The University of Michigan, Ann Arbor, MI 48109, USA. ; Universita di Perugia, Perugia, Italy. ; Lunar Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA. ; National Central University, Taipei, Taiwan. ; Departement of Physics, Oxford University, Oxford, UK. ; Institute for Planetary Research, Deutsches Zentrum fur Luft- und Raumfahrt (DLR), Berlin, Germany. Free University of Berlin, Institute of Geosciences, Malteserstrasse 74-100, Building Haus A, 12249 Berlin, Germany. ; Universita "Parthenope," Napoli, Italy. ; Helmholtz-Zentrum Berlin fur Materialien und Energie, Berlin, Germany. ; Osservatorio Astrofisico di Arcetri, INAF, Firenze, Italy. ; Agenzia Spaziale Italiana, Rome, Italy. ; NASA Jet Propulsion Laboratory, Pasadena, CA 91109, USA. Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742, USA. ; Istituto di Radioastronomia, INAF, Bologna, Italy. ; Institut fur Optische Sensorsysteme, DLR, Berlin, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25613895" target="_blank"〉PubMed〈/a〉

Description: Ceres is the largest asteroid-belt object and the Dawn spacecraft observed Ceres since 2015. Dawn observed two morphologically distinct linear features on Ceres’ surface: secondary crater chains and pit chains. Pit chains provide unique insights into Ceres’ interior evolution. We interpret pit chains called the Samhain Catenae as the surface expression of subsurface fractures. Using the pit chains’ spacings, we estimate that the localized thickness of Ceres’ fractured, outer layer is approximately ≥58 km, at least ~14 km greater than the global average. We hypothesize that extensional stresses, induced by a region of upwelling material arising from convection/diapirism, formed the Samhain Catenae. We derive characteristics for this upwelling material, which can be used as constraints in future interior modeling studies. For example, its predicted location coincides with Hanami Planum, a high-elevation region with a negative residual gravity anomaly, which may be surficial evidence for this proposed region of upwelling material.

Description: Although water vapour is the main species observed in the coma of comet 67P/Churyumov-Gerasimenko and water is the major constituent of cometary nuclei, limited evidence for exposed water-ice regions on the surface of the nucleus has been found so far. The absence of large regions of exposed water ice seems a common finding on the surfaces of many of the comets observed so far. The nucleus of 67P/Churyumov-Gerasimenko appears to be fairly uniformly coated with dark, dehydrated, refractory and organic-rich material. Here we report the identification at infrared wavelengths of water ice on two debris falls in the Imhotep region of the nucleus. The ice has been exposed on the walls of elevated structures and at the base of the walls. A quantitative derivation of the abundance of ice in these regions indicates the presence of millimetre-sized pure water-ice grains, considerably larger than in all previous observations. Although micrometre-sized water-ice grains are the usual result of vapour recondensation in ice-free layers, the occurrence of millimetre-sized grains of pure ice as observed in the Imhotep debris falls is best explained by grain growth by vapour diffusion in ice-rich layers, or by sintering. As a consequence of these processes, the nucleus can develop an extended and complex coating in which the outer dehydrated crust is superimposed on layers enriched in water ice. The stratigraphy observed on 67P/Churyumov-Gerasimenko is therefore the result of evolutionary processes affecting the uppermost metres of the nucleus and does not necessarily require a global layering to have occurred at the time of the comet's formation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Filacchione, G -- De Sanctis, M C -- Capaccioni, F -- Raponi, A -- Tosi, F -- Ciarniello, M -- Cerroni, P -- Piccioni, G -- Capria, M T -- Palomba, E -- Bellucci, G -- Erard, S -- Bockelee-Morvan, D -- Leyrat, C -- Arnold, G -- Barucci, M A -- Fulchignoni, M -- Schmitt, B -- Quirico, E -- Jaumann, R -- Stephan, K -- Longobardo, A -- Mennella, V -- Migliorini, A -- Ammannito, E -- Benkhoff, J -- Bibring, J P -- Blanco, A -- Blecka, M I -- Carlson, R -- Carsenty, U -- Colangeli, L -- Combes, M -- Combi, M -- Crovisier, J -- Drossart, P -- Encrenaz, T -- Federico, C -- Fink, U -- Fonti, S -- Ip, W H -- Irwin, P -- Kuehrt, E -- Langevin, Y -- Magni, G -- McCord, T -- Moroz, L -- Mottola, S -- Orofino, V -- Schade, U -- Taylor, F -- Tiphene, D -- Tozzi, G P -- Beck, P -- Biver, N -- Bonal, L -- Combe, J-Ph -- Despan, D -- Flamini, E -- Formisano, M -- Fornasier, S -- Frigeri, A -- Grassi, D -- Gudipati, M S -- Kappel, D -- Mancarella, F -- Markus, K -- Merlin, F -- Orosei, R -- Rinaldi, G -- Cartacci, M -- Cicchetti, A -- Giuppi, S -- Hello, Y -- Henry, F -- Jacquinod, S -- Reess, J M -- Noschese, R -- Politi, R -- Peter, G -- England -- Nature. 2016 Jan 21;529(7586):368-72. doi: 10.1038/nature16190. Epub 2016 Jan 13.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉INAF-IAPS, Istituto di Astrofisica e Planetologia Spaziali, Rome, Italy. ; LESIA, Observatoire de Paris/CNRS/UPMC/Universite Paris-Diderot, Meudon, France. ; Institute for Planetary Research, DLR, Berlin, Germany. ; Universite Grenoble Alpes, CNRS, IPAG, Grenoble, France. ; INAF-Osservatorio di Capodimonte, Napoli, Italy. ; UCLA, Los Angeles, California, USA. ; European Space Agency-ESTEC, Noordwijk, The Netherlands. ; Institut d'Astrophysique Spatial CNRS, Orsay, France. ; Dipartimento di Matematica e Fisica "Ennio De Giorgi", Universita del Salento, Lecce, Italy. ; Space Research Centre, Polish Academy of Sciences, Warsaw, Poland. ; NASA JPL, Pasadena, California, USA. ; Space Physics Research Laboratory, The University of Michigan, Michigan, Ann Arbor, USA. ; Universita di Perugia, Perugia, Italy. ; Lunar Planetary Laboratory, University of Arizona, Tucson, Arizona, USA. ; National Central University, Taipei, Taiwan. ; Department of Physics, Oxford University, Oxford, UK. ; Bear Fight Institute, Winthrop, Washington, USA. ; Helmholtz-Zentrum Berlin fur Materialien und Energie, Berlin, Germany. ; INAF-Osservatorio Astrofisico di Arcetri, Firenze, Italy. ; Agenzia Spaziale Italiana, Rome, Italy. ; Istituto di Radioastronomia-INAF, Bologna, Italy. ; Institute of Optical Sensor Systems, DLR, Berlin, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26760209" target="_blank"〉PubMed〈/a〉