| Description |
We propose to use the Herschel-PACS/SPIRE instruments to study the far-infrared
spectral properties of a sample of bright evolved binary stars. All these stars
are surrounded by a dusty circumbinary disc in a stable Keplerian orbit.
Mid-infrared spectroscopic studies show that these discs are the ideal environment
for strong dust processing, in the form of grain growth and crystallinisation.
Detailed disc modelling shows that the discs are not only very dusty, but also
that a non-negligible gas component must be present, to allow for the observed
disc geometry. The spectroscopic capabilities of Herschel will allow to extend
the spectroscopic information to the far-infrared, allowing the detection of
previously unexplored or unexpected dust and gas features. This will provide
invaluable information on the dust processing in the disc, and the relatively
unstudied gas component. |
