HD196885, The Most Extreme Planetary System?

Rare close binaries hosting giant planets offer an ideal laboratory to explore the properties and the stability of extreme planetary systems. In 2005, we identified one of the most extreme planetary with the discovery of a close (about 20 AU) secondary stellar companion to the exoplanet host HD196885A. Combining radial velocity observations and deep imaging, we derived the complete orbital parameters of the stellar binary (including its orbital inclination and its accurate mass). It enabled us to investigate the stability of the inner giant planet HD196885 Ab. Our dynamical simulations show that the system is currently and surprisingly more stable in a high mutual inclination configuration that falls in the Kozai resonance regime. If confirmed, this system would constitute one of the most compact non-coplanar systems known so far, and would raise several questions about its formation and stability.