Integrated Near-Infrared Band Strengths of Solid CH4 and Its Mixtures with N2

We studied icy CH4 and its mixtures with N2 (temperature 16-40 K), using near-IR transmittance spectroscopy (1.0-3.6 μm), and monitoring the film growth using interference patterns of two lasers. We measured peak position, full width at half-maximum, and strengths of the methane bands, and density and real refractive index of the icy films. Results confirm and extend but also partially contradict previous studies on similar mixtures. Experimental data can be applied to interpret observations of solar system (trans-Neptunian objects) and interstellar ices, where methane and nitrogen are believed to be present. We predict the optical depths of two methane NIR bands in the line of sight of some dense molecular clouds

Multiscale correlated analysis of the Aguas Zarcas CM chondrite

In this paper, we report the results of a campaign of measurements on four fragments of the CM Aguas Zarcas (AZ) meteorite, combining X‐ray computed tomography analysis and Fourier‐transform infrared (FT‐IR) spectroscopy. We estimated a petrologic type for our sampled CM lithology using the two independent techniques, and obtained a type CM2.5, in agreement with previous estimations. By comparing the Si‐O 10‐µm signature of the AZ average FT‐IR spectra with other well‐studied CMs, we place AZ in the context of aqueous alteration of CM parent bodies. Morphological characterization reveals that AZ has heterogeneous distribution of pores and a global porosity of 4.5 ± 0.5 vol%. We show that chondrules have a porosity of 6.3 ± 1 vol%. This larger porosity could be inherited due to various processes such as temperature variation during the chondrule formation and shocks or dissolution during aqueous alteration. Finally, we observed a correlation between 3D distributions of organic matter and mineral at micrometric scales, revealing a link between the abundance of organic matter and the presence of hydrated minerals. This supports the idea that aqueous alteration in AZ’s parent body played a major role in the evolution of the organic matter

Rationale for BepiColombo Studies of Mercury's Surface and Composition

BepiColombo has a larger and in many ways more capable suite of instruments relevant for determination of the topographic, physical, chemical and mineralogical properties of Mercury's surface than the suite carried by NASA's MESSENGER spacecraft. Moreover, BepiColombo's data rate is substantially higher. This equips it to confirm, elaborate upon, and go beyond many of MESSENGER's remarkable achievements. Furthermore, the geometry of BepiColombo's orbital science campaign, beginning in 2026, will enable it to make uniformly resolved observations of both northern and southern hemispheres. This will offer more detailed and complete imaging and topographic mapping, element mapping with better sensitivity and improved spatial resolution, and totally new mineralogical mapping. We discuss MESSENGER data in the context of preparing for BepiColombo, and describe the contributions that we expect BepiColombo to make towards increased knowledge and understanding of Mercury's surface and its composition. Much current work, including analysis of analogue materials, is directed towards better preparing ourselves to understand what BepiColombo might reveal. Some of MESSENGER's more remarkable observations were obtained under unique or extreme conditions. BepiColombo should be able to confirm the validity of these observations and reveal the extent to which they are representative of the planet as a whole. It will also make new observations to clarify geological processes governing and reflecting crustal origin and evolution. We anticipate that the insights gained into Mercury's geological history and its current space weathering environment will enable us to better understand the relationships of surface chemistry, morphologies and structures with the composition of crustal types, including the nature and mobility of volatile species. This will enable estimation of the composition of the mantle from which the crust was derived, and lead to tighter constraints on models for Mercury's origin including the nature and original heliocentric distance of the material from which it formed.Peer reviewe

Información Investigador: Brunetto Rodríguez de Cuinat, María del Rosario

Doctorado1536III - 2002; II - 2000155 - 2005; 115 - 2003; 91 - 2001Acoplamiento de técnicas cromatográficas con técnicas espectroscópicas. Determinación de sustancias tóxicas en leche materna. Efecto de la lovastatina en la arterioesclorosis y tripanosomiasis en conejos.Noviembre de 2005+58 274 2401375Facultad de [email protected]

Characterizing Irradiated Surfaces of Airless Bodies Using IR Spectroscopy.

International audienc

Hayabusa2/NIRS3 spectral observations of the surface of asteroid (162173) Ryugu

International audienceOn 27 June 2018, JAXA's Hayabusa2 spacecraft arrived at a distance of 20 km from its target 162173 Ryugu, a sub-km sized asteroid in the near-Earth space, and began its 1.5-year asteroid proximity operation. The NIRS3 instrument onboard Hayabusa2 acquired near-infrared (1.8-3.2 µm) reflectance spectra from the surface of Ryugu, to characterize and map its surface composition. The NIRS3 observations show that in this spectral range Ryugu is the darkest object to be observed up-close by a visiting spacecraft, and it is even darker than the nucleus of comet 67P/Churyumov-Gerasimenko. A weak, narrow absorption feature centered at 2.72 µm is detected across the entire observed surface, indicating that hydroxyl (OH)-bearing minerals are ubiquitous on the surface of Ryugu. The intensity of the OH feature and the extremely low albedo illustrate that the spectra of Ryugu are different from those of unheated phyllosilicate-rich carbonaceous chondrites. The best analogs are currently thermally- and/or shock-metamorphosed hydrous carbonaceous chondrites, and/or carbon-rich hydrated primitive materials exposed to some degree of space weathering. We will present the results of the analysis of the NIRS3 spectra, including the high-resolution data obtained during the descent operations

Laboratory perspectives on sample returns from Hayabusa2 and OSIRIS-REx

International audienc

Irradiation of meteorites: decoding space weathering on low albedo asteroids

International audienceIn this presentation I will review the role of irradiation laboratory experiments on the understanding of space weathering and the interpretation of VNIR reflectance spectra of small bodies

Flow analysis-hydride generation-gas phase derivative molecular absorption spectrophotometric determination of antimony in antileishmanial drugs

In the present work, the development of a method based on the coupling of flow analysis (FA), hydride generation (HG), and derivative molecular absorption spectrophotometry (D-EAM) in gas phase (GP), is described in order to determine total antimony in antileishmanial products. Second derivative order (D²224nm) of the absorption spectrum (190 - 300 nm) is utilized as measurement criterion. Each one of the parameters involved in the development of the proposed method was examined and optimized. The utilization of the EAM in GP as detection system in a continuous mode instead of atomic absorption spectrometry represents the great potential of the analytic proposal