Charge exchange in the colliding winds of Hot Jupiters and their host stars
Pascal Tremblin, CEA Saclay
Advisor: Eugene
Chiang, Berkeley
Abstract: This project investigates the charge exchange process between the atmospheric escape of a
hot jupiter and the wind of its host star as a possible explanation for the Lyman alpha high-velocity
absorption of the stellar spectrum observed during transits. We use 2D hydrodynamical simulation
to follow the dynamic of the two fluids (shocks, compression layers...) and we implement
a chemistry module to compute the quantity of neutral hydrogen produced by charge exchange.
The simulations show that Kelvin Helmholtz instabilities develop at the interface between the two
flows leading to a mixing that gives enough energetic neutral hydrogen to explain the observed
absorption. However works still need to be done, especially the implementation of coriolis force
due to the orbital motion of the planet, to achieve a steady state and get the correct geometry for
the interface.
PDF Presentation
Project report
