The Tarantula Massive Binary Monitoring project: II. A first SB2 orbital
  and spectroscopic analysis for the Wolf-Rayet binary R145
  We present the first SB2 orbital solution and disentanglement of the massive
Wolf-Rayet binary R145 (P = 159d) located in the Large Magellanic Cloud. The
primary was claimed to have a stellar mass greater than 300Msun, making it a
candidate for the most massive star known. While the primary is a known late
type, H-rich Wolf-Rayet star (WN6h), the secondary could not be so far
unambiguously detected. Using moderate resolution spectra, we are able to
derive accurate radial velocities for both components. By performing
simultaneous orbital and polarimetric analyses, we derive the complete set of
orbital parameters, including the inclination. The spectra are disentangled and
spectroscopically analyzed, and an analysis of the wind-wind collision zone is
conducted.
  The disentangled spectra and our models are consistent with a WN6h type for
the primary, and suggest that the secondary is an O3.5 If*/WN7 type star. We
derive a high eccentricity of e = 0.78 and minimum masses of M1 sin^3 i ~ M2
sin^3 i ~ 13 +- 2 Msun, with q = M2 / M1 = 1.01 +- 0.07. An analysis of
emission excess stemming from a wind-wind collision yields a similar
inclination to that obtained from polarimetry (i = 39 +- 6deg). Our analysis
thus implies M1 = 53^{+40}_{-20} and M2 = 54^{+40}_{-20} Msun, excluding M1 >
300Msun. A detailed comparison with evolution tracks calculated for single and
binary stars, as well as the high eccentricity, suggest that the components of
the system underwent quasi-homogeneous evolution and avoided mass-transfer.
This scenario would suggest current masses of ~ 80 Msun and initial masses of
Mi,1 ~ 105 and Mi,2 ~ 90Msun, consistent with the upper limits of our derived
orbital masses, and would imply an age of ~2.2 Myr.
