The Visible, InfraRed, and Thermal Imaging Spectrometer (VIRTIS) on Rosetta obtained hyperspectral images, spectral reflectance maps, and temperature maps of the asteroid 21 Lutetia. No absorption features, of either silicates or hydrated minerals, have been detected across the observed area in the spectral range from 0.4 to 3.5 micrometers. The surface temperature reaches a maximum value of 245 kelvin and correlates well with topographic features. The thermal inertia is in the range from 20 to 30 joules meter(-2) kelvin(-1) second(-0.5), comparable to a lunarlike powdery regolith. Spectral signatures of surface alteration, resulting from space weathering, seem to be missing. Lutetia is likely a remnant of the primordial planetesimal population, unaltered by differentiation processes and composed of chondritic materials of enstatitic or carbonaceous origin, dominated by iron-poor minerals that have not suffered aqueous alteration.

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New developments of photoinitiators are the base for the further extension of the radiation curing technology. Three different approaches are presented: The optimized combination of a bisacylphosphine oxide photoinitiator with a suitable stabilizer package allows the UV curing of clear coatings with an excellent performance in outdoor use. The design of new oxime ester derivatives allowed the introduction of a new tailor‐made photoinitiator for color filter resists applications that considerably improves the color quality of the color filter. A novel photoinitiator class capable of releasing strong amine bases opens new opportunities for expanding radiation curing into resins types that crosslink by base‐catalyzed processes.

International audienceThe VIRTIS (Visual IR Thermal Imaging Spectrometer) experiment has been one of the most successful experiments built in Europe for Planetary Exploration. VIRTIS, developed in cooperation among Italy, France and Germany, has been already selected as a key experiment for 3 planetary missions: the ESA-Rosetta and Venus Express and NASA-Dawn. VIRTIS on board Rosetta and Venus Express are already producing high quality data: as far as Rosetta is concerned, the Earth-Moon system has been successfully observed during the Earth Swing-By manouver (March 2005) and furthermore, VIRTIS will collect data when Rosetta flies by Mars in February 2007 at a distance of about 200 kilometres from the planet. Data from the Rosetta mission will result in a comparison – using the same combination of sophisticated experiments – of targets that are poorly differentiated and are representative of the composition of different environment of the primordial solar system. Comets and asteroids, in fact, are in close relationship with the planetesimals, which formed from the solar nebula 4.6 billion years ago. The Rosetta mission payload is designed to obtain this information combining in situ analysis of comet material, obtained by the small lander Philae, and by a long lasting and detailed remote sensing of the comet, obtained by instrument on board the orbiting Spacecraft. The combination of remote sensing and in situ measurements will increase the scientific return of the mission. In fact, the “in situ” measurements will provide “ground-truth” for the remote sensing information, and, in turn, the locally collected data will be interpreted in the appropriate context provided by the remote sensing investigation. VIRTIS is part of the scientific payload of the Rosetta Orbiter and will detect and characterise the evolution of specific signatures – such as the typical spectral bands of minerals and molecules – arising from surface components and from materials dispersed in the coma. The identification of spectral features is a primary goal of the Rosetta mission as it will allow identification of the nature of the main constituent of the comets. Moreover, the surface thermal evolution during comet approach to sun will be also studied

L W q ) MezC-O-UC14(THF) 1 2-= I >uci4 + U C I~ + Licl -1 Me2C-O-UC14(THF) 1 2 0.5 1 Scheme 2. The role of 1 as an intermediate i n the formation of 2two unsuspected points of the reaction mechanism. Firstly, acetone is not involved in the transformation 1 + 2, which is induced by Li/Hg reduction and generates UCI, and LiCI. Secondly, 2 is the true precursor of the alkene, tetramethylethylene. Indeed, 2 was smoothly reduced at 20 "C by Li/Hg to give a not yet identified uranium(rr1) alkoxide, and complete formation of the alkene could be achieved after the mixture was heated at reflux for 24 h. In agreement with these observations, the reductive coupling of acetone to give pinacol or tetramethylethylene was performed in a one-pot reaction by using the proper quantities of UCl, and Li/Hg; the diol was formed by hydrolysis after 8 h at room temperature, whereas the alkene was obtained by heating for 24 h under reflux (quantitative yields by NMR). When the UCl, and Na/Hg system was used, the yield of tetramethylethylene did not exceed 10% after 48 h at 65°C. This difficulty in forming the alkene could be clearly related to the sluggish reduction of the pinacolato intermediate 4, which was quite inert towards Na/Hg at 20 "C; even after 30 h at 65 "C only about 20 % was converted into tetramethylethylene. In contrast, 4 was readily reduced by Li/Hg and transformed completely into the expected alkene after 10 h in refl uxing tetrahydrofuran.We have found that in the reductive coupling of acetone, quite distinct conditions are necessary for both the coupling process leading to the pinacolate intermediates and for the subsequent deoxygenation step giving tetramethylethylene. These differences can be used to achieve remarkable selectivity like that observed with some titanium systems." 21 The results also underline the major role of the reducing agent, which determines the structure of the intermediates and is of particular importance in the deoxygenation step. If the first intermediate, a bimetallic species with a bridging OCMe,CMe,O ligand, readily reacts with the reducing agent to give a cyclic mononuclear metallopinacol, only this intermediate is transformed under more forcing conditions into the corresponding alkene. Experimental Procedure'H NMR (TMS int.): Bruker WP60 (60 MHz). All experiments were carried out under argon ( < 5 ppm oxygen and water) using standard Schlenk-vessel and vacuum-line techniques or in a glove box. Solvents were thoroughly dried and deoxygenated by standard methods and distilled immediately before use. 1 A mixture of UCI, (354 mg. 0.93 mmol). 1 % Li/Hg (640 mg, 0.93 mmol of Li), and acetone (68 gL, 0.93 mmol) in THF (15 mL) was stirred for 3 h at 20°C. The green solution was filtered and its volume reduced to 5 mL. The green microcrystals of 1 that precipitated upon addition of pentane (10 mL) were filtered off, washed with pentane, and dried under vacuum (464 mg, 90%). 2: By using the same procedure as for 1 , green microcrystals of 2 were isolaled in 76% yield from the reaction of UCI, (3...

Carbon dioxide (CO) is one of the most abundant species in cometary nuclei, but because of its high volatility, CO ice is generally only found beneath the surface. We report the infrared spectroscopic identification of a CO ice-rich surface area located in the Anhur region of comet 67P/Churyumov-Gerasimenko. Spectral modeling shows that about 0.1% of the 80- by 60-meter area is CO ice. This exposed ice was observed a short time after the comet exited local winter; following the increased illumination, the CO ice completely disappeared over about 3 weeks. We estimate the mass of the sublimated CO ice and the depth of the eroded surface layer. We interpret the presence of CO ice as the result of the extreme seasonal changes induced by the rotation and orbit of the comet.

MUPUS, the multi purpose sensor package onboard the Rosetta lander PHILAE, will measure the energy balance and the physical parameters in the near-surface layers -up to about 30 cm depth-of the nucleus of Rosetta's target comet Churyumov-Gerasimenko. Moreover it will monitor changes in these parameters over time as the comet approaches the sun. Among the parameters studied are the density, the porosity, cohesion, the thermal diffusivity and conductivity, and temperature. The data should increase our knowledge of how comets work, and how the coma gases form. The data may also be used to constrain the microstructure of the nucleus material. Changes with time of physical properties will reveal timescales and possibly the nature of processes that modify the material close to the surface. Thereby, the data will indicate how pristine cometary matter sampled and analysed by other experiments on PHILAE really is.

In preparation for the ESA/JAXA BepiColombo mission to Mercury, thematic working groups had been established for coordinating the activities within the BepiColombo Science Working Team in specific fields. Here we describe the scientific goals of the Geodesy and Geophysics Working Group (GGWG) that aims at addressing fundamental questions regarding Mercury’s internal structure and evolution. This multidisciplinary investigation will also test the gravity laws by using the planet Mercury as a proof mass. The instruments on the Mercury Planetary Orbiter (MPO), which are devoted to accomplishing the GGWG science objectives, include the BepiColombo Laser Altimeter (BELA), the Mercury orbiter radio science experiment (MORE), and the MPO magnetometer (MPO-MAG). The onboard Italian spring accelerometer (ISA) will greatly aid the orbit reconstruction needed by the gravity investigation and laser altimetry. We report the current knowledge on the geophysics, geodesy, and evolution of Mercury after the successful NASA mission MESSENGER and set the prospects for the BepiColombo science investigations based on the latest findings on Mercury’s interior. The MPO spacecraft of the BepiColombo mission will provide extremely accurate measurements of Mercury’s topography, gravity, and magnetic field, extending and improving MESSENGER data coverage, in particular in the southern hemisphere. Furthermore, the dual-spacecraft configuration of the BepiColombo mission with the Mio spacecraft at higher altitudes than the MPO spacecraft will be fundamental for decoupling the internal and external contributions of Mercury’s magnetic field. Thanks to the synergy between the geophysical instrument suite and to the complementary instruments dedicated to the investigations on Mercury’s surface, composition, and environment, the BepiColombo mission is poised to advance our understanding of the interior and evolution of the innermost planet of the solar system.