Found 2 talks width keyword Moon

Thursday September 23, 2010
Dr. Javier Licandro
Instituto de Astrofísica de Canarias, Spain


In this talk we present spectroscopy of asteroids 24 Themis and 65 Cybele in the 2-4 μ region obtained with the NASA 3.5m IRTF telescope. Their spectra are very similar, and present the typical water ice band at 3.1 μ and additional absorption bands in the 3.2-3.4 μ region that can be attributed to solid organics, showing that there is a small amount of water ice and solid organics widely distributed across their surface. Spectra in the 6-25 μ region obtained with SPITZER of 65 Cybele also show that its surface is covered by a fine anhydrous silicate grains mantle as other outer belt asteroids like the Trojans are. This dust mantle, with a small amount of water ice and complex organic solids, is similar to comet surface where non-equilibrium phases coexist. The presence of water-ice and anhydrous silicates is indicative that hydration did not happened or is incomplete, suggesting that the temperatures were always sufficiently low. This is the first detection of water ice and and solid organics in the surface of an asteroid and suggest that these materials are much more abundant than expected in the surface of asteroids with semi-major axis a > 3 AU. The cosmogonical and astrobiological relevance of this discovery will be discussed.

Friday June 12, 2009
Dr. Enric Pallé Bago
Instituto de Astrofísica de Canarias, Spain


Of the 342 planets discovered so far orbiting other stars, 58 'transit' the stellar disk, meaning that they can be detected by a periodic decrease in the starlight flux. The light from the star passes through the atmosphere of the planet, and in a few cases the basic atmospheric composition of the planet can be estimated. As we get closer to finding analogues of Earth, an important consideration toward the characterization of exoplanetary atmospheres is what the transmission spectrum of our planet looks like. Here we report the optical and near-infrared transmission spectrum of the Earth, obtained during a lunar eclipse. Some biologically relevant atmospheric features that are weak in the reflected spectrum (such as ozone, molecular oxygen, water, carbon dioxide and methane) are much stronger in the transmission spectrum, and indeed stronger than predicted by modeling. We also find the fingerprints of the Earth's ionosphere and of the major atmospheric constituent, diatomic nitrogen (N2), which are missing in the reflected spectrum. Our results indicate that the technique of transit spectroscopy of rocky planets may be a very powerful tool for exoplanet atmospheric characterization, and is likely to provide the first detection of a habitable exobiosphere.

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