X-Shooting ULLYSES XI. OB stars in LMC, SMC

We have determined physical and wind properties of 97 LMC and 77 SMC massive stars, ranging from O2 to B9 subtypes, representing the majority of the XShootU OB sample (OeBe and candidate SB2 systems are excluded). Results are broadly in agreement with previous optical spectroscopic studies, with evolutionary masses spanning 12-117M_{sun}_ in the LMC and 11-74M_{sun}_ in the SMC. We have determined a revised Teff - spectral type calibration for Magellanic Cloud stars, identified stars with peculiar radial velocities, and compared wind properties of high luminosity O stars with dense winds, revealing ~0.27dex higher wind momenta of LMC stars with respect to SMC counterparts.

Incorporating the recent empirical metallicity dependence of Z^0.22^ for wind velocities, this suggests a mass-loss dependence of Z^0.5^ for luminous O stars. Studies incorporating ultraviolet mass-loss diagnostics are required for OB stars with weak winds and/or low luminosities.