The Tarantula Massive Binary Monitoring

R 144 is the visually brightest WR star in Large Magellanic Cloud (LMC). was reported to be a binary, making it potentially most massive binary thus observed. We perform comprehensive spectral, photometric, orbital, and polarimetric analysis of 144. an eccentric (e=0.51) 74.2-d comprising two relatively evolved (age~2 Myr), H-rich stars. The hotter primary (WN5/6h, T=50 kK) cooler secondary (WN6/7h,T=45kK) have nearly equal masses. combination low rotation H-depletion observed system well reproduced by contemporary evolution models that include boosted mass-loss at upper-mass end. systemic velocity its relative isolation suggest ejected as runaway from neighbouring 136 cluster. optical light-curve shows clear orbital modulation can explained processes: excess emission stemming wind-wind collisions double wind eclipses. Our model implies inclination i=60.4+-1.5deg, resulting accurately constrained dynamical masses 74+-4 69+-4 Msun. Assuming both components are core H-burning, these difficult reconcile with derived luminosities (logL1,2 = 6.44, 6.39 [Lsun]), which correspond evolutionary order 110 100Msun, respectively. Taken face value, our results imply stars high classical Eddington factors Gamma_e 0.78+-0.1. If on main sequence, their radii (~25Rsun) they only slightly inflated, even this factor. Alternatively, could core-He burning, strongly inflated regular size Wolf-Rayet (~1Rsun), scenario help resolve mass discrepancy.