Hot UV bright stars in globular clusters

We have obtained medium-resolution spectra of seven UV-bright stars discovered on images of four southern globular clusters obtained with the Ultraviolet Imaging Telescope (UIT). Effective temperatures, surface gravities and helium abundances are derived from LTE and non-LTE model atmosphere fits. Three of the stars have sdO spectra, including M4-Y453 (T-eff = 58800 K, log g = 5.15), NGC 6723-III60 (T-eff = 40600 K, log g = 4.46) and NGC 6752-B2004 (T-eff = 37000 K, log g = 5.25). All seven stars lie along either post-extended horizontal branch (EHB) or post-early AGE evolutionary tracks. The post-early AGE stars show solar helium abundances, while the post-EHB stars are helium deficient, similar to their EHB progenitors.