Ambient and cold-temperature infrared spectra and XRD patterns of ammoniated phyllosilicates and carbonaceous chondrite meteorites relevant to Ceres and other solar system bodies

Mg‐phyllosilicate‐bearing, dark surface materials on the dwarf planet Ceres have NH_4‐bearing materials, indicated by a distinctive 3.06 μm absorption feature. To constrain the identity of the Ceres NH_4‐carrier phase(s), we ammoniated ground particulates of candidate materials to compare their spectral properties to infrared data acquired by Dawn's Visible and Infrared (VIR) imaging spectrometer. We treated Mg‐, Fe‐, and Al‐smectite clay minerals; Mg‐serpentines; Mg‐chlorite; and a suite of carbonaceous meteorites with NH_4‐acetate to exchange ammonium. Serpentines and chlorites showed no evidence for ammoniation, as expected due to their lack of exchangeable interlayer sites. Most smectites showed evidence for ammoniation by incorporation of NH_4^+ into their interlayers, resulting in the appearance of absorptions from 3.02 to 3.08 μm. Meteorite samples tested had weak absorptions between 3.0 and 3.1 μm but showed little clear evidence for enhancement upon ammoniation, likely due to the high proportion of serpentine and other minerals relative to expandable smectite phases or to NH_4^+ complexing with organics or other constituents. The wavelength position of the smectite NH4 absorption showed no variation between IR spectra acquired under dry‐air purge at 25 °C and under vacuum at 25 °C to −180 °C. Collectively, data from the smectite samples show that the precise center wavelength of the characteristic ~3.05 μm v_3 absorption in NH_4 is variable and is likely related to the degree of hydrogen bonding of NH_4‐H_2O complexes. Comparison with Dawn VIR spectra indicates that the hypothesis of Mg‐saponite as the ammonium carrier phase is the simplest explanation for observed data, and that Ceres dark materials may be like Cold Bokkeveld or Tagish Lake but with proportionally more Mg‐smectite

Hyperspectral Imaging of HEDs: A new Approach to Investigate VNIR Spectral Properties of Meteorites

We present a preliminary study on VNIR hyperspectral imaging of HED samples. We integrate the high spatial resolution VNIR images acquired by SPIM with the mineral chemistry, Scanning Electron Microscope element maps and petrographic description

SeaBIRD: A Flexible and Intuitive Planetary Datamining Infrastructure

Description of SeaBIRD (Searchable and Browsable Infrastructure for Repository of Data), a software and hardware infrastructure for multi-mission planetary datamining, with web-based GUI and API set for the integration in users' software

Characterization of V-type asteroids orbiting in the middle and outer main belt

We present new spectral observations using ground-based telescopes of 23 putative V-type asteroids, selected according to colour surveys in the visible from the Moving Objects Catalogue of the Sloan Digital Sky Survey and near-infrared from the Moving Objects VISTA catalogue. 10 asteroids are orbiting in the middle main belt, while five in the outer part of the main asteroid belt. For the observed asteroids, we assign a taxonomical classification and confirm the basaltic nature for 16 of them. The high-quality spectra in the UV range, obtained with the X-Shooter spectrograph at ESO, allowed the identification of the Fe2+ forbidden transition of pyroxene for 10 asteroids. This band is centred at 506.5 nm, and it is diagnostic of the Ca-content in the pyroxene form. We determined a low Fe-content composition for asteroids (2452) Lyot, (5758) Brunini, (7675) Gorizia, (9197) Endo, (22308) 1990 UO4, (36118) 1999 RE135, (66905) 1999 VC160, and (189597) 2000 WG119, and a composition more rich in Fe for asteroids (75661) 2000 AB79 and (93620) 2000 UQ70. We also present a dynamical investigation of V-type asteroids in the middle and outer main belt. The principal finding of these simulations is that the middle and outer V-types are more likely to be associated with some families, which were considered as possibly originated from the break up of a partially or totally differentiated parent body by diverse studies. This reinforces the hypothesis that the identified V-type in the region were not originated from (4) Vesta and that the number of differentiated objects in the middle and outer main belt must have been much larger than previously assumed

IDIS Small Bodies and Dust Node: Technical innovation and science

This work was supported by the EUROPLANET RI FP7 grant agreement 228319It is not trivial, nowadays, to be fully aware of the impressive amount of astrophysical resources that are at hand. Virtual Observatories (VOs) were therefore created to provide a simple access to what astronomers look for. In this paper we focus on the original data access services developed specifically, in a VO perspective, for the "Small Bodies and Dust Node" (SBDN) in the framework of the Integrated and Distributed Information System (IDIS) initiative of the Europlanet Research Infrastructure project. We describe the scientific goals, along with the innovative technical aspects, of the tools that SBDN presently provides to the scientific community, namely the Comet Emission Lines service, and the Cosmic Dust Catalog service. In the former, an algorithm for the detection of unidentified emission lines has been implemented

First mineralogical maps of 4 Vesta

Before Dawn arrived at 4 Vesta only very low spatial resolution (~50 km) albedo and color maps were available from HST data. Also ground-based color and spectroscopic data were utilized as a first attempt to map Vesta’s mineralogical diversity [1-4]. The VIR spectrometer [5] onboard Dawn has ac-quired hyperspectral data while the FC camera [6] ob-tained multi-color data of the Vestan surface at very high spatial resolutions, allowing us to map complex geologic, morphologic units and features. We here re-port about the results obtained from a preliminary global mineralogical map of Vesta, based on data from the Survey orbit. This map is part of an iterative map-ping effort; the map is refined with each improvement in resolution

Phase structure and thermal evolution in coating films and powders obtained by sol-gel process : Part II. ZrO2–2.5 mole% Y2O3

Powders and coatings of zirconia doped with 2.5 mole % yttria have been produced via the sol-gel route. The phase structure and subsequent thermal evolution in heating and cooling cycles have been investigated using mainly perturbed angular correlations spectroscopy. Thermal analyses and XRD as a function of temperature have also been performed to obtain complementary information. Upon heating, the amorphous gels crystallized into the tetragonal structure and showed the same hyperfine pattern and thermal behavior as observed in tetragonal zirconia obtained by the ceramic route: the two configurations of vacancies around zirconium ions denoted as t1 and t2 forms and their mutual t1 → t2 transformation. While the powder sample exhibited an incipient thermal instability above 1000 °C and underwent completely the t2 form to m–ZrO2 transition during subsequent, gradual cooling below 500 °C, the coating retained the tetragonal phase within the whole temperature range investigated. Hyperfine results suggest that the tetragonal phase stabilization is favored by the highly defective nature of the t1 form and consequently hardened by the availability of oxygen. The PAC derived activation energy for the fast diffusion of the oxygen vacancies inherent to the t2 form was determined as 0.54 ± 0.14 eV.Facultad de Ciencias Exacta

Artifacts reduction in VIR/Dawn data

Remote sensing images are generally affected by different types of noise that degrade the quality of the spectral data (i.e., stripes and spikes). Hyperspectral images returned by a Visible and InfraRed (VIR) spectrometer onboard the NASA Dawn mission exhibit residual systematic artifacts. VIR is an imaging spectrometer coupling high spectral and spatial resolutions in the visible and infrared spectral domain (0.25-5.0 μm). VIR data present one type of noise that may mask or distort real features (i.e., spikes and stripes), which may lead to misinterpretation of the surface composition. This paper presents a technique for the minimization of artifacts in VIR data that include a new instrument response function combining ground and in-flight radiometric measurements, correction of spectral spikes, odd-even band effects, systematic vertical stripes, high-frequency noise, and comparison with ground telescopic spectra of Vesta and Ceres. We developed a correction of artifacts in a two steps process: creation of the artifacts matrix and application of the same matrix to the VIR dataset. In the approach presented here, a polynomial function is used to fit the high frequency variations. After applying these corrections, the resulting spectra show improvements of the quality of the data. The new calibrated data enhance the significance of results from the spectral analysis of Vesta and Ceres

Ambient and cold-temperature infrared spectra and XRD patterns of ammoniated phyllosilicates and carbonaceous chondrite meteorites relevant to Ceres and other solar system bodies

Mg‐phyllosilicate‐bearing, dark surface materials on the dwarf planet Ceres have NH_4‐bearing materials, indicated by a distinctive 3.06 μm absorption feature. To constrain the identity of the Ceres NH_4‐carrier phase(s), we ammoniated ground particulates of candidate materials to compare their spectral properties to infrared data acquired by Dawn's Visible and Infrared (VIR) imaging spectrometer. We treated Mg‐, Fe‐, and Al‐smectite clay minerals; Mg‐serpentines; Mg‐chlorite; and a suite of carbonaceous meteorites with NH_4‐acetate to exchange ammonium. Serpentines and chlorites showed no evidence for ammoniation, as expected due to their lack of exchangeable interlayer sites. Most smectites showed evidence for ammoniation by incorporation of NH_4^+ into their interlayers, resulting in the appearance of absorptions from 3.02 to 3.08 μm. Meteorite samples tested had weak absorptions between 3.0 and 3.1 μm but showed little clear evidence for enhancement upon ammoniation, likely due to the high proportion of serpentine and other minerals relative to expandable smectite phases or to NH_4^+ complexing with organics or other constituents. The wavelength position of the smectite NH4 absorption showed no variation between IR spectra acquired under dry‐air purge at 25 °C and under vacuum at 25 °C to −180 °C. Collectively, data from the smectite samples show that the precise center wavelength of the characteristic ~3.05 μm v_3 absorption in NH_4 is variable and is likely related to the degree of hydrogen bonding of NH_4‐H_2O complexes. Comparison with Dawn VIR spectra indicates that the hypothesis of Mg‐saponite as the ammonium carrier phase is the simplest explanation for observed data, and that Ceres dark materials may be like Cold Bokkeveld or Tagish Lake but with proportionally more Mg‐smectite