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This poster presents newly obtained circumstellar 12C17O and 12C18O line observations, from which the line intensity are then related directly to the 17O/18O surface abundance ratio for a sample of nine AGB stars covering the three spectral types (). These ratios are evaluated in relation to a fundamental stellar evolution parameters: the stellar initial mass. The 17O/18O ratio is shown to function as an effective method of determining the initial stellar mass. Through comparison with predictions by stellar evolution models, accurate initial mass estimates are calculated for all nine sources.

Poster #219