The masses of the neutron and donor star in the high-mass X-ray binary IGR J18027-2016 A. B. Mason, A. J. Norton, J. S. Clark, I. Negueruela and P. Roche A&A, 532 (2011) A124 Published online: 04 August 2011 DOI: 10.1051/0004-6361/201117392