25 citations · 46 across the 3 of their papers we have counts for
3 papers · 1 filter
On the masses of neutron stars
M. H. van Kerkwijk, J. van Paradijs, E. J. Zuiderwijk
We analyze the currently available observations of X-ray binaries in a consistent way, to re-determine the masses of the neutron stars in these systems. In particular, our attentio…
Spectroscopy of HD 77581 and the mass of Vela X-1
M. H. van Kerkwijk, J. van Paradijs, E. J. Zuiderwijk +3
We present new high-resolution, high signal-to-noise optical spectra of HD 77581, the optical counterpart of the X-ray source Vela X-1, and determine radial velocities from these s…
WRAY 977 (GX301-2): A HYPERGIANT WITH PULSAR COMPANION
L. Kaper, H. J. G. L. M. Lamers, E. Ruymaekers +2
Wray 977, the B supergiant companion of the X-ray pulsar GX301-2, should be classified as B1~Ia+, based on a comparison of its optical spectrum to that of zeta1 Sco, a well-known B…