Ordinary Meeting: Debris Disks

Friday 27th March 2015 - 8:00pm
Topic: Dusty debris around sun-like stars as a sign of planetary systems.

Speaker:  Dr Jonathan Marshall, UNSW
Venue: Epping Creative Centre - 26 Stanley Road, Epping
Abstract: Circumstellar debris discs around mature, main-sequence stars are a visible remnant of the planet formation process and therefore a marker of planetary systems around their host stars. These debris systems are tenuous rings of dusty material, comprised of bodies ranging from micron-sized dust grains to kilometre-size planetesimals (asteroids and comets), analogous to the asteroid belt and Edgeworth-Kuiper belt in our solar system. Most commonly detected from measurement of the thermal emission from their constituent dust at mid- and far-infrared wavelengths, a few systems have also been observed by starlight scattered from the dust at optical wavelengths. In this talk I will present imaging observations of debris discs, revealing how we trace the presence of unseen planets in the structure of the disc and how linking the three critical components of planetary systems - stars, planets and dust - into a single coherent picture will help us to identify the timescales and outcomes of planet formation, and therefore the incidence of planteary systems similar to our own elsewhere in the galaxy.

Biography: Dr Marshall gained his MSci degree at the University of St Andrws  and a MSc at the University of London.  He gained his PhD at the Open University.  His primary research interest iscircumstellar debris discs as evidence of planetary systems around mature, main-sequence stars.