Séminaire Doctoral / Seminar PhD |
| « Exoplanets and brown dwarfs hunting using microlensing » |
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Clément Ranc |
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I will discuss briefly the fundamental concepts of microlensing planet searches using gravitational microlensing. I will try to show how the strength and peculiarities of the method flow from the basic manner in which planets are discovered. In particular, microlensing is sensitive to very low mass planets on wide orbits and free-floating planets, and can be used to search for planets orbiting host stars with a broad range of masses and Galactocentric distances. However, microlensing events are rare and can’t be predicted in advance, the majority of the host stars are extremely faint, and the planetary signals typically last less than a day that makes the interpretation of light curves challenging as for the microlensing event MOA 2007-BLG-197.
I will take some time to show you how can we discover a brown dwarf while we are looking for a planet, and why the first feeling we may have (“ disappointment”) can be overcome by all the wonderful challenges that surround the formation mystery of such objects. Finally, I will show how interferometry, linked to a real time analysis of microlensing events in a Bayesian framework will open a new way to constrain masses of stellar black holes, stars and planets up to the Galactic Bulge of the Milky way. Why coming? There will be some food and soft. Some beautiful artistic pictures because Nature is Beauty. Because you like exoplanets, and you wonder how can we use microlensing? Because you don’t like exoplanets: I won’t speak about the ~2000 exoplanets discovered, just about brown dwarfs, caustics, interferometry and multiple images |
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mercredi 6 mai 2015 - 17:00 Salle Entresol Daniel Chalonge, Institut d'Astrophysique |
| Page web du séminaire / Seminar's webpage |