Near-infrared spatially resolved spectroscopy of (136108) Haumea's multiple system

The transneptunian region of the solar system is populated by a wide variety of icy bodies showing great diversity. The dwarf planet (136108) Haumea is among the largest TNOs and displays a highly elongated shape and hosts two moons, covered with crystalline water ice like Hamuea. Haumea is also the largest member of the sole TNO family known to date. A catastrophic collision is likely responsible for its unique characteristics. We report here on the analysis of a new set of observations of Haumea obtained with SINFONI at the ESO VLT. Combined with previous data, and using light-curve measurements in the optical and far infrared, we carry out a rotationally resolved spectroscopic study of the surface of Haumea. We describe the physical characteristics of the crystalline water ice present on the surface of Haumea for both regions, in and out of the Dark Red Spot (DRS), and analyze the differences obtained for each individual spectrum. The presence of crystalline water ice is confirmed over more than half of the surface of Haumea. Our measurements of the average spectral slope confirm the redder characteristic of the spot region. Detailed analysis of the crystalline water-ice absorption bands do not show significant differences between the DRS and the remaining part of the surface. We also present the results of applying Hapke modeling to our data set. The best spectral fit is obtained with a mixture of crystalline water ice (grain sizes smaller than 60 micron) with a few percent of amorphous carbon. Improvements to the fit are obtained by adding ~10% of amorphous water ice. Additionally, we used the IFU-reconstructed images to measure the relative astrometric position of the largest satellite Hi`iaka and determine its orbital elements. An orbital solution was computed with our genetic-based algorithm GENOID and our results are in full agreement with recent results.Comment: Accepted for publication in A&

The spectrum of (136199) Eris between 350 and 2350 nm: Results with X-Shooter

X-Shooter is the first second-generation instrument for the ESO-VLT. It as a spectrograph covering the 300 - 2480 nm spectral range at once with a high resolving power. These properties enticed us to observe (136199) Eris during the science verification of the instrument. The target has numerous absorption features in the optical and near-infrared domain which has been observed by different authors, showing differences in their positions and strengths. We attempt at constraining the existence of super-volatiles, e.g., CH4, CO and N2, and in particular try to understand the physical-chemical state of the ices on Eris' surface. We observed Eris in the 300-2480 nm range and compared the newly obtained spectra with those available in the literature. We identified several absorption features, measuring their positions and depth and compare them with those of reflectance of pure methane ice obtained from the optical constants of this ice at 30 K to study shifts in their positions and find a possible explanation for their origin. We identify several absorption bands in the spectrum all consistent with the presence of CH4 ice. We do not identify bands related with N2 or CO. We measured the central wavelengths of the bands and find variable shifts, with respect to the spectrum of pure CH4 at 30 K. Conclusions. Based on these wavelength shifts we confirm the presence of a dilution of CH4 in other ice on the surface of Eris and the presence of pure CH4 spatially segregated. The comparison of the centers and shapes of these bands with previous works suggest that the surface is heterogeneous. The absence of the 2160 nm band of N2 can be explained if the surface temperature is below 35.6 K, the transition temperature between the alpha and beta phases of this ice. Our results, including the reanalysis of data published elsewhere, point to an heterogeneous surface on Eris.Comment: 15 pages, 5 figure

Etude comparative des propriétés physico-chimiques d'astéroïdes, de satellites glacés et d'objets transneptuniens

Asteroids, satellites and transneptunian objects are three populations of bodies which present dynamical, physical and chemical properties extremely varied. The present thesis is dedicated to the physical-chemical analysis of the surface of asteroids, icy moons and transneptunian objects from ground based observations. An essential part of the thesis is devoted to the data analysis with the use of pipelines reduction or specially developed routines. In the process of my research, a spectrum of the near-Earth asteroid (175706) 1996 FG3 was obtained. A part of the work is devoted to the analysis of the icy satellites, the jovian moons Europa and Ganymede, both targets of the JUICE space mission, selected by ESA in 2012. A full mapping was made for the Europa’s surface in order to localize precisely the hydrated regions of the moon. A large part of the work was dedicated to the data analysis of the Uranus’ satellite Miranda. This study shows that water ice is crystalline in the major part of its surface including regions unobserved by Voyager 2. New results were obtained for three transneptunian objects (TNO), including two dwarf planets. Finally, a study of the dwarf planet Haumea was carried out in order to compare its different regions, including that of the Dark Red Spot (DRSThe astrometric positions of the two Haumea’s satellites (Hi’iaka and Namaka) were measured as well. A series of laboratory experiments (Institut de Planétologie et d’Astrophysique de Grenoble) was accomplished on methanol ice using a cryostat with a setting liquid deposition in a cell. This work enabled to obtain new absorbance spectra in the near infrared by varying the temperature. These results permit new detailed reflectance models for solar system objects containing methanol.Les astéroïdes, les satellites et les objets transneptuniens sont trois populations qui rassemblent de nombreux objets dont les propriétés dynamiques, physiques et chimiques sont extrêmement variées. Cette thèse est dédiée à la caractérisation physico-chimique des surfaces d’astéroïdes, de satellites glacés et d’objets transneptuniens observés à partir du sol terrestre. Une partie importante de ma thèse a été consacrée à l’analyse de données avec l’utilisation de procédures d’analyse de données propres aux instruments ou de programmes que j’ai spécialement développés. Concernant les satellites glacés, mes recherches m’ont apporté des données sur des lunes joviennes Europe et Ganymède, toutes deux cibles de la mission spatiale JUICE sélectionnée par l’ESA en 2012. Ces résultats m’ont permis de réaliser une cartographie de la surface d’Europe et donc de localiser les régions plus ou moins hydratées de cette lune.. Une grande partie de mon travail a consisté à analyser des données de Miranda, satellite d’Uranus. Cette étude montre que la glace d’eau est cristalline dans la majorité de sa surface. J’ai par la suite obtenu des résultats sur trois objets transneptuniens dont deux planètes naines. Enfin, par l’étude détaillée des spectres de la planète naine Hauméa, j’ai pu comparer et analyser ses différentes régions, notamment celle de la tache rouge et sombreJ’ai enfin effectué un séjour à l’IPAG (Institut de Planétologie et d’Astrophysique de Grenoble). Dans ce cadre, j’ai réalisé en laboratoire une série d’expériences sur la glace de méthanol à basse pression en utilisant un cryostat avec une mise en dépôt liquide dans une cellule. En faisant varier la température, j’ai pu obtenir de nouveaux spectres en absorbance dans le domaine proche infrarouge. Ces résultats rendent donc possible l’utilisation de modèles de réflectance plus détaillés pour les objets du système solaire contenant du méthanol. 

Etude comparative des propriétés physico-chimiques d'astéroïdes, de satellites glacés et d'objets transneptuniens

Asteroids, satellites and transneptunian objects are three populations of bodies which present dynamical, physical and chemical properties extremely varied. The present thesis is dedicated to the physical-chemical analysis of the surface of asteroids, icy moons and transneptunian objects from ground based observations. An essential part of the thesis is devoted to the data analysis with the use of pipelines reduction or specially developed routines. In the process of my research, a spectrum of the near-Earth asteroid (175706) 1996 FG3 was obtained. A part of the work is devoted to the analysis of the icy satellites, the jovian moons Europa and Ganymede, both targets of the JUICE space mission, selected by ESA in 2012. A full mapping was made for the Europa s surface in order to localize precisely the hydrated regions of the moon. A large part of the work was dedicated to the data analysis of the Uranus satellite Miranda. This study shows that water ice is crystalline in the major part of its surface including regions unobserved by Voyager 2. New results were obtained for three transneptunian objects (TNO), including two dwarf planets. Finally, a study of the dwarf planet Haumea was carried out in order to compare its different regions, including that of the Dark Red Spot (DRSThe astrometric positions of the two Haumea s satellites (Hi iaka and Namaka) were measured as well. A series of laboratory experiments (Institut de Planétologie et d Astrophysique de Grenoble) was accomplished on methanol ice using a cryostat with a setting liquid deposition in a cell. This work enabled to obtain new absorbance spectra in the near infrared by varying the temperature. These results permit new detailed reflectance models for solar system objects containing methanol.Les astéroïdes, les satellites et les objets transneptuniens sont trois populations qui rassemblent de nombreux objets dont les propriétés dynamiques, physiques et chimiques sont extrêmement variées. Cette thèse est dédiée à la caractérisation physico-chimique des surfaces d astéroïdes, de satellites glacés et d objets transneptuniens observés à partir du sol terrestre. Une partie importante de ma thèse a été consacrée à l analyse de données avec l utilisation de procédures d analyse de données propres aux instruments ou de programmes que j ai spécialement développés. Concernant les satellites glacés, mes recherches m ont apporté des données sur des lunes joviennes Europe et Ganymède, toutes deux cibles de la mission spatiale JUICE sélectionnée par l ESA en 2012. Ces résultats m ont permis de réaliser une cartographie de la surface d Europe et donc de localiser les régions plus ou moins hydratées de cette lune.. Une grande partie de mon travail a consisté à analyser des données de Miranda, satellite d Uranus. Cette étude montre que la glace d eau est cristalline dans la majorité de sa surface. J ai par la suite obtenu des résultats sur trois objets transneptuniens dont deux planètes naines. Enfin, par l étude détaillée des spectres de la planète naine Hauméa, j ai pu comparer et analyser ses différentes régions, notamment celle de la tache rouge et sombreJ ai enfin effectué un séjour à l IPAG (Institut de Planétologie et d Astrophysique de Grenoble). Dans ce cadre, j ai réalisé en laboratoire une série d expériences sur la glace de méthanol à basse pression en utilisant un cryostat avec une mise en dépôt liquide dans une cellule. En faisant varier la température, j ai pu obtenir de nouveaux spectres en absorbance dans le domaine proche infrarouge. Ces résultats rendent donc possible l utilisation de modèles de réflectance plus détaillés pour les objets du système solaire contenant du méthanol.PARIS-Observatoire (751142302) / SudocMEUDON-Observatoire (920482302) / SudocSudocFranceF

Laboratory Measurements Of Pure And Diluted Methanol In Water Ice In The Nir And Mir Wavelength Ranges.

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Laboratory Measurements Of Pure And Diluted Methanol In Water Ice In The Nir And Mir Wavelength Ranges.

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Spectroscopic observations of the Uranus' satellite Miranda in Near-IR

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Laboratory Measurements Of Pure And Diluted Methanol In Water Ice In The Nir And Mir Wavelength Ranges.

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Surface Heterogeneity of the dwarf-planet Haumea

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High-contrast observations of the Haumea system

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