Gaps, rings, and spirals in scattered light: Discs observed around Herbig Ae/Be and T-Tauri stars

Planets form in the discs of gas and dust that encircle newly formed protostars. The growing planets accrete disc material, creating annular gaps, and the disc/planet gravitational interaction results in spiral waves in the disc structure. Since the protoplanet itself is essentially undetectable at this early stage it is these large-scale perturbations that are regarded as the fingerprints of on-going planet formation.

Although on solar system scales these planet-forming discs may be very large (extending to many 100 AUs) the nearest such objects are on the order of 100 parsecs away. Thus a planet-forming disc may only subtend an arcsecond as seen from the Earth. Fortunately we are currently in a golden age of high-resolution instrumentation enabling us to probe the structure of protoplanetary discs in unprecedented detail. Our team is fortunate to have data on a large sample of these so-called transitional discs, taken with instruments such as Gemini's GPI and the VLT's SPHERE.

The aim of this project is to model this wealth of observational data using our sophisticated radiative-transfer code TORUS. These models will enable us to determine the structure of the protoplanetary discs as well as the composition of the dust within them, and will thus help us to identify the conditions necessary for planet formation.