Found 33 talks width keyword exoplanets
Friday June 12, 2009
Dr. Enric Pallé BagoInstituto de Astrofísica de Canarias, Spain
AbstractOf 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.
Thursday January 29, 2009
Dr. Christopher WatsonUniversity of Belfast, Northern Ireland
AbstractSuperWASP is the UK's leading extra-solar planet detection program, having detected 22 of the 52 transiting planets known to date. This stems from the instruments ability to image ~500 square degrees every 60sec down to 16th mag (equivalent to the whole visible sky every 20 minutes). Recent experiments have shown that the data from SuperWASP can be reduced with 1 min of it being obtained and with further software development we will be able to identify transient sources within minutes of their observation. Detailed analysis of SuperWASP-N data has shown many populations of transient objects, including rapidly variable objects, which seem to correspond to extremely faint objects in the Sloan survey. Spectroscopy of these objects has proved challenging.
Thursday October 30, 2008
Living with a red dwarf: X-ray and UV emissions of red dwarf stars and effects on hosted planets and their suitability for life
Prof. Edward GuinanVillanova University, USA
AbstractRed Dwarf (dM) stars are the most numerous stars in our Galaxy. These faint, cool, long-lived, and low mass stars make up > 80% of all stars in the Universe. Determining the number of red dwarfs with planets and assessing planetary habitability (a planet’s potential to develop and sustain life) are critically important because such studies would indicate how common life is in the universe. Our program - "Living with a Red Dwarf" addresses these questions by investigating the long-term nuclear evolution and magnetic-dynamo coronal and chromospheric X-ray to Ultraviolet properties of red dwarf stars with widely different ages. The major focus of the program is to study the magnetic-dynamo generated X-ray-Ultraviolet emissions and flare properties of red dwarf stars from youth to old age. Emphasized are how the stellar X-UV emissions, flares & winds affect hosted planets and impact their habitability. We have developed age-rotation-activity relations and also are constructing irradiance tables (X-UV fluxes) that can be used to model the effects of X-UV radiation on planetary atmospheres and on possible life on nearby hosted planets. Despite the earlier pessimistic view that red dwarfs stars are not suitable for habitable planets - mainly because their low luminosities require a hosted planet to orbit quite close (r <0.3 AU) to be sufficiently warm to support life. Our initial results indicate that red dwarf stars (in particular the warmer dM stars) can indeed be suitable hosts for habitable planets capable of sustaining life for hundreds of billion years. Some examples of red dwarf stars currently known to host planets are discussed.
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