Imaging the dynamical processes in the inner regions of protoplanetary discs, Astrophysics Group – Physics PhD (Funded)

The University of Exeter’s College of Engineering, Mathematics and Physical Sciences is inviting applications for a fully-funded PhD studentship to commence in September 2020 or as soon as possible thereafter. For eligible students the studentship will cover UK/EU tuition fees plus an annual tax-free stipend of at least £15,009 for 3.5 years full-time, or pro rata for part-time study. The student would be based in the Astrophysics Group on the Streatham Campus in Exeter.

Project Description:

The discs around young stars provide the stage for planet formation and the dominant fraction of the planet population is believed to form in the very inner regions of these discs, on scales of a few astronomical units. Photometric monitoring observations indicate that highly dynamical processes are taking place in this inner disc environment, but it is unclear whether the observed flux modulations are due to the presence of planets that dynamically sculpt the disc or other disc-related phenomena, such as dusty disc winds or gravitational instabilities.

So far, observational studies have been strongly limited by the achieved angular resolution, as even the largest telescopes are only able to resolve the outer disc regions, on scales of tens to hundreds of astronomical units. Infrared interferometry offers an elegant way to overcome this resolution barrier by coherently combining the light from separate smaller telescopes. As part of an Exeter-led instrumentation project we recently achieved the first 6-telescope interferometric observations on young stars and obtain now direct images of the innermost astronomical unit of protoplanetary discs.

The aim of this project is to use these unique new capabilities in order to study the time evolution of the inner disc environment. The project is linked to a large 100+ night survey at the CHARA and VLTI array and a rich data set of protoplanetary disc observations is already available. At the achieved extremely high angular resolution (0.001 arcsecond, or 1/5,000,000 of a degree), the Keplerian timescale is of the order of just a few months, which allow us to follow the temporal evolution of any disc asymmetries as they orbit around the star. From this work we expect new insights on the origin of the photometric variability in young stars and on the processes that govern planet formation and planet migration near the dust sublimation region.

As part of your PhD you will learn about the physics of protoplanetary discs and planet formation, plan and conduct interferometric observations, and analyse data from the VLTI and CHARA array. You will work within our team of postgraduate students and postdoctoral researchers and interact closely with Exeter theory expert for the physical interpretation. The position offers opportunities to travel to Chile and/or the United States to conduct observations, work with our collaborators, and to present your results at international conferences.

This award provides annual funding to cover UK/EU tuition fees and a tax-free stipend. For students who pay UK/EU tuition fees the award will cover the tuition fees in full, plus at least £15,009 per year tax-free stipend.
The studentship will be awarded on the basis of merit for 3.5 years of full-time study to commence in September 2020.