Abstract

Recent observations of protoplanetary discs have shown clear evidence of warps and misalignments, where the disc is best described with an orientation that changes as a function of the distance from the central star. A number of scenarios have been proposed to explain the origins of these misalignments, including the presence of a hidden companion on an orbit that is misaligned with respect to the outermost disc. By introducing such a misaligned body we need to consider the potential of disc precession, inclination damping and alignment time-scales. I will show how an understanding of these effects can allow us to infer what is happening in these systems with observed misalignments and the implications for their long term evolution. This tour will include applications to TW Hya (a rapidly moving shadow), misalignments induced by a flyby and rocking shadows.