Based on spectrophotometric observations from the Guillermo Haro Observatory ( Cananea , Mexico ) , a study of the spectral properties of the complete sample of 24 blue straggler stars ( BSs ) in the old Galactic open cluster M67 ( NGC2682 ) is presented .
All spectra , calibrated using spectral standards , were re-calibrated by means of photometric magnitudes in the Beijing-Arizona-Taipei-Connecticut system , which includes fluxes in 11 bands covering \sim 3500 - 10000 Â Ã .
The set of parameters was obtained using two complementary approaches that rely on a comparison of the spectra with ( a ) an empirical sample of stars with well-established spectral types and ( b ) a theoretical grid of optical spectra computed at both low and high resolution .
The overall results indicate that the BSs in M67 span a wide range in T _ { eff } ( \sim 5600 - 12600 Â K ) and surface gravities that are fully compatible with those expected for main sequence objects ( \log { g } = 3.5 - 5.0 Â dex ) .