Events Calendar

Sébastien Fromang (CEA) : « Shear-driven instabilities and shocks in the atmosphere of hot Jupiters »

Thursday 09 November 2017, 13:00 - 14:00
by Mickaël BONNIN

Hot Jupiters are giants gaseous planets orbiting very close to their central star. Because of the extreme irradiation they receive, the dynamics of their atmosphere is different from that of the solar system giant planets. In the past few years, general ciculation models of the atmosphere of hot Jupiters 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 developped to study such fast flows. In particular, the question of the jet stability and the possible presence of shocks in hot hot Jupiters 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 Kevin-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.

Location : Salle de réunion du bât. 9