Towards the mysterious origins of warm Jupiters

Kurzfassung

The origins of warm Jupiters (WJs) are unclear. If they formed beyond the snow line, far from their host stars, then migration is required to bring them to their current orbits. It is unclear, however, which migration mechanism(s) are the most important. Obliquity (the angle between the stellar rotation and planetary orbital axes) is a key tracer of migration history. Dynamically violent, high-eccentricity migration leads to planets in significantly misaligned orbits with large obliquities, whereas disc-driven migration should result in orbits coplanar with the stellar equator. In contrast to the hot Jupiters, the imprint of dynamical migration in WJs should not be erased through tidal interactions with the convective zone of their stars, because they are tidally detached. We have a VLT/ESPRESSO programme to measure the obliquities of an unbiased sample of eleven WJs, which will greatly increase the size of the measured sample. Here we present the motivation, target selection, and latest results from this observing programme.