2021 Project Description

Occultations of stars by debris discs

Supervisors

Sascha Zeegers, Jonathan Marshall, Matthew Kenworthy, Ciska Kemper, Lapo Fanciullo, Alfonso Trejo-Cruz, Gilles Otten
Find out more about supervisors on ASIAA website

Task Description and Goals

Debris discs are belts of planetesimals around stars. The planetesimals are comparable to asteroids and comets and the belts are thus analogous to the Asteroid and Edgeworth-Kuiper belts in the Solar system. These discs consist of bodies from the size of Pluto all the way down to tiny dust grains.
Some nearby debris discs have been spatially resolved and, although we cannot directly observe the dust-producing planetesimals, we do observe dusty rings around these stars. The dust is generated in collisions between the planetesimals. Stirring of the disc, either by an external planet or interactions between the most massive planetesimals, starts a cascade of collisions.
The collisions in the disc provide interesting information about the disc. Observing the debris resulting from collisions would, for instance, make it possible to put constraints on the particle-size distribution in debris discs. This in turn tells us about the rigid strength of the planetesimals that collided to produce the dust.

By observing a background star that passes behind a debris disc, we may be able to directly observe these collisions, because the dust generated during a collision will cause the background star to dim slightly.

• Investigate for which of the resolved debris discs have debris discs with occultating background stars by searching the databases (e.g. Hubble Space Telescope and Very Large Telescope, ESO Paranal).
• Modelling of dust-producing collisions in a debris disc in order to predict what we may observe.

Required Background

• Communication skills in English
• Basic knowledge of physics
• Familiarity with computer programming (preferably Python)
• Some knowledge of general astronomy (not essential)