| 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. |
