Spin-orbit angles as a probe to orbital evolution

Abstract

The WASP (Wide Angle Search for Planets) has discovered 75 planets in the Southern Hemisphere. We followed-up 40 of these and observed the Rossiter-McLaughlin effect. It allows us to measure the angle between the stellar spin and the planet's orbital spin. Here, we present the results of our survey, along with results published in the literature.Our observations reveal a wide distribution in orbital angle, indicative or past dynamical interactions. Our data also demonstrates the important effects that tidal interactions have in altering the spin-orbitdistribution. This renders any interpretation tricky. However, comparing different sub-samples we start uncovering evidence that two types of migration are maybe acting to create the hot Jupiter population.