Mass loss rates along the red giant branch (RGB) and along the
asymptotic giant branch (AGB) are a key ingredient for a proper
understanding of these evolutionary phases of low-mass stars.

This program aims at deriving the mass loss rates of AGB and RGB
stars of different luminosities in the galactic globular cluster
47 Tuc. A search for possible dust-enshrouded AGB stars will also be
performed in four different fields. The cluster 47 Tuc is especially
well suited for this study, because (i) it is the closest stellar
cluster whose AGB and RGB are well populated, (ii) previous
studies have assigned giants to either the RGB or AGB,
(iii) the AGB of metal-rich globular clusters
like 47 Tuc extends to luminosities Mbol ~ - 4.6 higher than in
metal-poor globular clusters, and (iv) its distance is well known.

In addition, this program will provide a ([12]-[25], [25]-[60])
color-color diagram for giants of known luminosity and evolutionary
state (AGB or RGB), to which the colors of galactic field
stars may then be compared. With such a ''Rosetta stone'',
it is possible to test the conjecture according to which all M giants
with no excesses in the ([12]-[25], [25]-[60]) diagram are RGB
stars, thus providing a powerful tool for testing the evolutionary
status of field giants.