"Before Planets: The Mineralogy and Chemistry of Pre-Planetary Disks" Chris Wright, University of New South Wales (abstract at the bottom of this message)

"Before Planets: The Mineralogy and Chemistry of Pre-Planetary Disks" Chris Wright, University of New South Wales. Planets form within the circumstellar disks around young stars. Samples of the solid material – or dust in astronomical parlance – comprising our own primitive disk are found in meteorites and interplanetary dust particles. Using the powerful technique of astronomical mid-infrared spectroscopy, including polarimetry, it is possible to ascertain the composition of the dust existing within the envelopes and/or disks around young stars. I will present new mid-infrared spectropolarimetric observations obtained with TIMMI2 at the ESO 3.6 m telescope from 2004 to 2006. I will examine implications for dust grain properties - such as mineralogy, chemistry and shape - around objects in various stages of the stellar evolution cycle, from the young to the old, as well as those of dust grains in the diffuse interstellar medium. The most exciting result has been the detection of a narrow polarisation band at 11.2 microns toward the embedded YSO IRAS 13481-6124, which may indicate the presence of a crystalline olivine component to the dust. Further, I will present a selection of spatially resolved mid-IR spectroscopy results obtained with T-ReCS on Gemini-S of beta Pictoris, HR 4796A and HD 100546, as well as other embedded sources. Finally, I will present ATCA mm- and cm-wave continuum and molecular observations which resolve some structural details of the HD 100546 disk.

Location:  Leiden, room 431

Time: Monday 15 September, 11:00 hrs