A spectroscopic multiplicity survey of Galactic Wolf-Rayet stars. III. The northern late-type nitrogen-rich sample

Context. Massive stars are powerful cosmic engines that have a huge impact on their surroundings and host galaxies. The majority of massive will interact with companion star during evolution. effects this interaction end-of-life products currently poorly constrained. In the phases immediately preceding core-collapse, in Galaxy Mi ≳ 20 M⊙ may appear as classical Wolf-Rayet (WR) stars. multiplicity properties WR population thus required to further our understanding stellar evolution at upper-mass end.