In this work, we characterize the properties of HB stars in the GCs {omega} Cen and NGC 6752. We use dedicated model atmospheres and synthetic spectra grids computed using a hybrid LTE/NLTE modeling approach to fit the MUSE spectra of HB stars hotter than 8000K in both clusters. The spectral fits provide estimates of the effective temperature (Teff), surface gravity (logg), and helium abundance of the stars. The model grids are further used to fit the HST magnitudes, meaning the spectral energy distributions (SED), of the stars. From the SED fits, we derive the average reddening, radius, luminosity, and mass of the stars in our sample. The atmospheric and stellar properties that we derive for the stars in our sample are in good agreement with the theoretical expectations. We use three different diagnostics, namely the position of the G-jump and changes in metallicity and helium abundances to place the onset of diffusion in the stellar atmospheres at Teff between 11 and 11.5kK. Our sample includes two stars known as photometric variables, we confirm one to be a bona fide extreme HB object but the other is a blue straggler star. Finally, unlike what has been reported in the literature, we do not find significant differences between the properties of the stars in both clusters.

Cone search capability for table J/A+A/677/A86/tableb1 (Atmospheric parameters for stars in NGC 6752)

Cone search capability for table J/A+A/677/A86/tableb2 (Atmospheric parameters for stars in {omega} Cen)

Cone search capability for table J/A+A/677/A86/tableb3 (SED fit results (Teff free) for NGC 6752)

Cone search capability for table J/A+A/677/A86/tableb4 (SED fit results (Teff free) for {omega} Cen)

Cone search capability for table J/A+A/677/A86/tableb5 (SED fit results (Teff fixed) for NGC 6752)

Cone search capability for table J/A+A/677/A86/tableb6 (SED fit results (Teff fixed) for {omega} Cen)