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B. F. Williams (UWa), P. Battinelli (RomeObs), Y. Efremov (SternbergInst), P. W. Hodge (UWa), E. Magnier (UHaw)
We present color magnitude diagrams of four blue massive and compact star clusters in M31: G38, G44, G94, and G293. The diagrams of the four clusters reveal a well-populated upper main sequence and various numbers of supergiants. The U-B and B-V colors of the upper main sequence stars are used to determine reddening estimates of the different lines of sight in the M31 disk. Reddening values range from EB-V = 0.20±0.10 to 0.31±0.11. We statistically remove field stars on the basis of completeness, magnitude and color. Isochrone fits to the field-subtracted, reddening-corrected diagrams yield age estimates ranging from 63±15 Myr to 160±60 Myr. G38 and G44 are located to the south south-west of the giant OB association NGC 206. We find the ages of both G38 and G44 to be 100± 40 Myr. These clusters may have been formed by the same mechanism that has caused the formation of NGC 206 if the density wave interaction located at NGC 206 has been propagating through the southern half of M31 at ~32 km/s with respect to the stars in the disk for the past 100 Myr. This propagation velocity is also consistent with the age distribution of the Cepheid population near NGC 206 (Magnier et al. 1997). Support for this work was provided by NASA through grant number GO-06459.01-95A from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555.