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==> In this proposal, more time is being requested for PWESSELI.YSOAEBE
==> In this proposal, more time is being requested for CWAELKEN.VEGASTAR
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A novel result from ISO is the richness of the spectra of the
oxygen-rich dust surrounding some stars, in particular young stars
the circumstellar disks of which have not yet been dispersed.
The new dust features can be attributed to crystalline silicates:
the match with laboratory results about such silicates, in particular
those from the Allende meteorite, is remarkable.
The study of these stars may yield clues for the evolution from the
amorphous silicates of the interstellar medium to the crystalline ones
that are observed in meteorites, comets and interplanetary dust particles.
The new emission features essentially all fall in the spectral window
(20-80 micron) that has been opened to spectroscopy by ISO and that will
be closed again for a long time after the end of the mission.
The purpose of the present observations is to observe these features
with the best achievable accuracy for selected bright objects, in order
to construct a database that will be fundamental for the study of
the mineralogy of oxygen rich dust.