Multiplicity of massive O stars and evolutionary implications
  Nearby companions alter the evolution of massive stars in binary systems. Using a sample of Galactic massive stars in nearby young clusters, we simultaneously measure all intrinsic binary characteristics relevant to quantify the frequency and nature of binary interactions. We find a large intrinsic binary fraction, a strong preference for short orbital periods and a flat distribution for the mass-ratios. Our results do not support the presence of a significant peak of equal-mass `twin' binaries. As a result of the measured distributions, we find that over seventy per cent of all massive stars exchange mass with a companion. Such a rate greatly exceeds previous estimates and implies that the majority of massive stars have their evolution strongly affected by interaction with a nearby companion. 
H. Sana, S.E. de Mink, A. de Koter, N. Langer, C.J. Evans, M. Gieles,   E. Gosset, R.G. Izzard, J.-B. Le Bouquin, F.R.N. Sch...
astro-ph.SR astro-ph.CO