HST medium-band imaging of M32

Instead, the age of the asymptotic giant branch (AGB) population is likely to be the primary factor. The ratio of AGB to red giant branch stars in M32 is similar to that of the inner disc of M31 which contain stars that formed 1.5-4Gyr ago. If the M32 population is at the older end of this age then its lack of C-stars may be consistent with a narrow mass range for carbon star formation predicted by some stellar evolution models.

Applying our chemical classifications to the dusty variable stars identified with Spitzer, we find that the x-AGB candidates identified with Spitzer are predominately M-type stars. This substantially increases the lower limit to the cumulative dust-production rate in M32 to >1.20x10^-5^M_{sun}_/yr.