Mousis O.,University of Franche Comte |
Hueso R.,University of the Basque Country |
Beaulieu J.-P.,French National Center for Scientific Research |
Bouley S.,University Paris - Sud |
And 58 more authors.
Experimental Astronomy | Year: 2014
Amateur contributions to professional publications have increased exponentially over the last decades in the field of planetary astronomy. Here we review the different domains of the field in which collaborations between professional and amateur astronomers are effective and regularly lead to scientific publications.We discuss the instruments, detectors, software and methodologies typically used by amateur astronomers to collect the scientific data in the different domains of interest. Amateur contributions to the monitoring of planets and interplanetary matter, characterization of asteroids and comets, as well as the determination of the physical properties of Kuiper Belt Objects and exoplanets are discussed. © 2014, Springer Science+Business Media Dordrecht.
Ceamanos X.,CNRS Grenoble Institute for Particle Astrophysics and Cosmology Laboratory |
Ceamanos X.,Meteo - France |
Doute S.,CNRS Grenoble Institute for Particle Astrophysics and Cosmology Laboratory |
Fernando J.,University Paris - Sud |
And 6 more authors.
Journal of Geophysical Research E: Planets | Year: 2013
This article addresses the correction for aerosol effects in near-simultaneous multi-angle observations acquired by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) aboard the Mars Reconnaissance Orbiter. In the targeted mode, CRISM senses the surface of Mars using 11 viewing angles, which allow it to provide unique information on the scattering properties of surface materials. In order to retrieve these data, however, appropriate strategies must be used to compensate the signal sensed by CRISM for aerosol contribution. This correction is particularly challenging as the photometric curve of these suspended particles is often correlated with the also anisotropic photometric curve of materials at the surface. This article puts forward an innovative radiative transfer-based method named Multi-angle Approach for Retrieval of Surface Reflectance from CRISM Observations (MARS-ReCO). The proposed method retrieves photometric curves of surface materials in reflectance units after removing aerosol contribution. MARS-ReCO represents a substantial improvement regarding previous techniques as it takes into consideration the anisotropy of the surface, thus providing more realistic surface products. Furthermore, MARS-ReCO is fast and provides error bars on the retrieved surface reflectance. The validity and accuracy of MARS-ReCO is explored in a sensitivity analysis based on realistic synthetic data. According to experiments, MARS-ReCO provides accurate results (up to 10% reflectance error) under favorable acquisition conditions. In the companion article, photometric properties of Martian materials are retrieved using MARS-ReCO and validated using in situ measurements acquired during the Mars Exploration Rovers mission. Key Points Correction method for aerosol effects in CRISM/MRO multi-angle observations Accurate reflectance estimates are retrieved as surface anisotropy is considered Surface reflectance estimates are provided with error bars ©2012. American Geophysical Union. All Rights Reserved.
Kahane C.,CNRS Grenoble Institute for Particle Astrophysics and Cosmology Laboratory |
Ceccarelli C.,CNRS Grenoble Institute for Particle Astrophysics and Cosmology Laboratory |
Faure A.,CNRS Grenoble Institute for Particle Astrophysics and Cosmology Laboratory |
Caux E.,University Of Toulouse Ups Omp |
Caux E.,Hoffmann-La Roche
Astrophysical Journal Letters | Year: 2013
Formamide (NH2CHO), the simplest possible amide, has recently been suggested to be a central species in the synthesis of metabolic and genetic molecules, the chemical basis of life. In this Letter, we report the first detection of formamide in a protostar, IRAS 16293-2422, which may be similar to the Sun and solar system progenitor. The data combine spectra from the millimeter and submillimeter TIMASSS survey with recent, more sensitive observations at the IRAM 30 m telescope. With an abundance relative to H 2 of ∼10-10, formamide appears as abundant in this solar-type protostar as in the two high-mass star-forming regions, Orion-KL and SgrB2, where this species has previously been detected. Given the largely different UV-illuminated environments of the three sources, the relevance of UV photolysis of interstellar ices in the synthesis of formamide is therefore questionable. Assuming that this species is formed in the gas phase via the neutral-neutral reaction between the radical NH2 and H2CO, we predict an abundance in good agreement with the value derived from our observations. The comparison of the relative abundance [NH2CHO]/ [H2O] in IRAS 16293-2422 and in the coma of the comet Hale-Bopp supports the similarity between interstellar and cometary chemistry. Our results thus suggest that the abundance of some cometary organic volatiles could reflect gas phase rather than grain-surface interstellar chemistry. © 2013. The American Astronomical Society. All rights reserved.