1996A&A...311..879R

We present an infrared and optical study of the massive X-ray binary 2S 0114+650 = LSI +65 010. We present new data obtained as a part of the Southampton/Valencia long-term monitoring campaign of massive X-ray binaries, consisting of optical spectra, infrared photometry and both wide (Johnson) and narrow (Stroemgren) optical photometry. The data cover the period 1990-1995. The analysis of these data lead us to assess that it is a supergiant of spectral type B1 and luminosity class Ia. We are able to determine the astrophysical parameters by using empirical calibrations obtained for the Stroemgren photometric system. We explain the X-ray luminosity in terms of a simple wind-fed model, by which matter expelled from the optical companion via a stellar wind is accreted onto the neutron star.