Sébastien Fromang
Service Astroph. (SAp), IRFU, CEA-Saclay (Gif-sur-Yvette, France)
Amphithéâtre Henri Mineur, Institut d'Astrophysique de Paris
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| « Shear-driven instabilities and shocks in the atmospheres of hot Jupiters » |
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Sébastien Fromang |
| Hot Jupiters are giant gaseous planets orbiting very close to their central star. Because of the extreme irradiation they receive, the dynamics of the atmosphere is different from that of the solar system giant planets. In the past few years, general circulation models of the atmosphere of hot Jupiter have shown in particular the existence of a supersonic eastward equatorial jet. Yet these results have mostly been obtained using numerical methods that were initially developed to study the earth atmosphere and which may not be well adapted to study such fast flows. In particular, the question of the jet stability and the possible presence of shocks is hot Jupiter atmospheres have been widely discussed in the literature in the past few years. In this talk, I will present the results of a series of high resolution simulations specifically designed to address these shortcomings. I will show that the jet is indeed destabilized by two instabilities of Kelvin-Helmoltz type respectively associated with the meridional and vertical velocity shears. These instabilities induce significant flow variability and weak shocks in the upper layers of the atmosphere and may affect their temperature-pressure profile as well as the internal structure of hot Jupiters. |
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vendredi 30 septembre 2016 - 11:00 Amphithéâtre Henri Mineur, Institut d'Astrophysique de Paris |
| Page web du séminaire / Seminar's webpage |