Contents of: VI/111/./abstract/TTANABE_MCCLUS_2.abs

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With known distances and metallicities and with a wide range of age,
globular clusters (GCs) in the Magellanic Clouds (MCs) offer an excellent
opportunity for observational studies of stellar evolution.  In order to make
clear the evolution of late stages of stars and, especially, the mass-loss
phenomenon and its effects on stellar evolution, we proposed in our GT
proposal, TTANABE.REDSTAR3, to observe systematically the GCs in the MCs using
3 LW filters of ISOCAM.  Several GCs have already been observed with ISO and
our preliminary analysis shows that there is at least one very red, infrared
stars in each of NGC 1978 and NGC 1846 which are both intermediate-age
clusters.
These stars are very red and invisible even at K-band.  They are thought
to be luminous AGB stars which clearly stand apart from the other, visible,
AGB stars in that they have much thicker dust shells resulting from heavier
mass-loss.  We thus believe that they are in the final stage of their AGB
evolution, the superwind phase.  If so, we have a very good chance to study
stars in this phase because their ages and masses can be estimated.
We here propose to observe spectrophotometrically these infrared stars in
NGC 1978 and NGC 1846 with ISOCAM CVF and ISOPHT.  ISO observations will
enable us with the full spectral energy distributions of these stars up to
60 microns, which enables us to determine their luminosity accurately as well
as their spectral types.  The mass of dust shell and the mass-loss rate can
also be estimated.  With these information we can elucidate the nature of the
stars in the late evolutionary stage and the mass-loss phenomenon.  All these
can be used to test the current theory of stellar evolution.
Although this is not a proposal to request "more time", we think that this
proposal is the extension of our open time proposal, TTANABE.MCCLUS, which is
(was) to observe NGC 1783 and NGC 419 in the same way as this proposal.