Thesis Topic: Dust dynamics in young debris disks
Thesis Supervisor: Johan Olofsson
Abstract
Debris disks are very good analogues of the Kuiper belt of the solar system, and they are detected around ~20% of main sequence stars. The presence of dust particles is inferred either via the thermal re-processing (at far infrared and millimeter wavelengths) or the scattering of the stellar light (at optical and near-infrared wavelengths, see Figure 1). These particles collide with each other and are eventually blown away and removed from the disk; their lifetime is much shorter than the age of the stars. This implies that dust is constantly being produced, which happens in a so-called collisional cascade, where the largest, km-sized, bodies are grinded down. The detection of debris disks is a direct confirmation that the formation of large planetesimals is an efficient process during the first 10 Myr of the star formation process. By studying the dust properties and dynamics, thanks to high angular resolution observations, we can better constrain the dust production mechanism as well as the properties of their parent bodies, crucial to inform planet formation models.
The proposed PhD thesis aims at combining (multiwavelength) observations and simulations, to better constrain the properties and dynamics of the particles that we observe in debris disks. The successful applicant will work on observations obtained with several instruments (SPHERE, ALMA, or GRAVITY) and perform numerical simulations to interpret them. Some disks that will be studied are asymmetric and eccentric which can furthermore inform us about the presence of additional perturbers (binary or companions).
Figure 1: near-infrared scattered light observations of four debris disks obtained with the SPHERE instrument at the VLT. The disks are highly inclined and seen from the side. By using state-of-the-art dynamical models, we can constrain the spatial distribution of the dust particles, as well as their reflectance properties (related to their size, composition, porosity).