| Description |
We propose to use the Herschel-PACS/SPIRE instruments to study the
far-infrared continuum emission of a sample of evolved stars.
All these stars are proven or suspected post-AGB binaries surrounded
by a long-lived circumbinary disc. Our analysis of SPITZER mid-infrared
spectra of these stars showed that grain processing is very efficient in
these discs, despite the very short evolutionary timescale of the
post-AGB central star. Extending the spectral energy distribution (SED)
to far-infrared wavelengths is an essential complement in constraining
the disc characteristics. The long-wavelength flux is very sensitive to the
amount of large grains, and thus the total dust mass, and grain-size
distribution within the disc. The ultimate goal is to study the structure,
formation and evolution of the very common discs around evolved
binary stars, and constrain their impact on the evolution of the binary
systems. |
