The R136 star cluster dissected with <i>Hubble</i> Space Telescope/STIS

Context: The star cluster R136 inside the LMC hosts a rich population of massive stars, including most stars known. strong stellar winds these very luminous impact their evolution and surrounding environment. We currently lack detailed knowledge wind structure that is needed to quantify this impact. Aims: To observationally constrain properties in R136, particular parameters related clumping. Methods: simultaneously analyse optical UV spectroscopy 53 O-type 3 WNh-stars using FASTWIND model atmosphere code genetic algorithm. models account for optically thick clumps effects porosity velocity-porosity, as well non-void interclump medium. Results: obtain parameters, surface abundances, mass-loss rates, terminal velocities clumping characteristics compare theoretical predictions evolutionary models. include density medium velocity-porosity wind. For first time, are systematically measured wide range effective temperatures luminosities. Conclusions: confirm age 1.0-2.5 Myr derive an initial mass $\geq 250 {\rm M}_\odot$ our sample, R136a1. sample highly clumped, with average factor $f_{\rm cl}=29\pm15$. find tentative trends wind-structure function rate, suggesting higher rates less clumped. several observed none satisfactorily reproduces both quantities. prescription Krti\v{c}ka & Kub\'at (2018) matches best rates.