Contents of: VI/111/./abstract/AMANCHAD_PAGB.abs

The following document lists the file abstract/AMANCHAD_PAGB.abs from catalogue VI/111.
A plain copy of the file (without headers/trailers) may be downloaded.

  We propose to obtain full range spectra (SWS and LWS) of a well
 defined sample of heavily obscured post-AGB stars recently discovered
 during an extensive multi-wavelength survey of bright IRAS sources
 with far-IR colors similar to those of PNe.
  They have recently left the AGB phase and are surrounded by thick
 circumstellar shells, showing no optical counterpart (or extremely
 faint) in the visible range and emitting most of their energy in the
  Most of them are non-variable OH/IR stars, showing OH maser emission
 at 1612 MHz, but with a low IRAS variability index, indicating
 that the thermal pulses and the strong mass loss suffered by
 these stars at the end of the AGB have recently stopped and they are
 now post-AGB stars on their way to become new PNe.
  In a few cases, radio continuum emission has also been detected,
 indicating that the ionization of the envelope has already started
 even although nothing is yet visible in the optical range.
  We want to determine their global energy distribution to reconstruct
 their mass loss history and study the properties of the dust.
 This will be used to test the most recent models of AGB and post-AGB
 evolution which suggest that there is a correlation between the
 mass and age of these stars and their evolutionary tracks on the
 IRAS two-color diagram.
  ISO is the only instrument capable to obtain information about
 these stars as nothing can be extracted from observations in other
 wavelength ranges. Moreover, the targets included in this proposal are
 among the brightest infrared emitters between 2.4 and 197 microns,
 and SWS and LWS spectra will completely cover this spectral range.

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