Dr. Tim Pearce (University of Warwick, UK)

Title: "Are there planets at debris-disc edges?"

Abstract:

In the Solar System, Neptune dominates the inner edge of the Kuiper Belt. We can see structures like the Kuiper Belt in extrasolar systems too; these are 'debris discs', which are concentrations of extrasolar asteroids, comets, dust etc.. For decades, we tended to assume that debris discs in the outer regions of planetary systems host unseen planets at their inner edges, akin to Neptune and the Kuiper Belt. Such planets would dynamically interact with debris, potentially leaving clues about the planets' masses and orbits. However, the inferred planets were almost always too small to be detected, so their existence is unclear. In this talk I discuss what we expect such planets to do to observed discs, what evidence there is for these planets, and what it would mean if they do not actually exist. Now that JWST gives us our first opportunity to detect some of these inferred planets, and is searching for them right now, we are poised to shed new light on this long-posed question.