RXTE observations of the X-ray binary 2S 0114+650

Observations from the proportional counter array experiment on board the Rossi X-Ray Timing Explorer (RXTE) of the temporal and spectral properties of the high-mass X-ray binary 2S 0114+ 650 are reported. We find highly variable X-ray emission modulated at a period of 2.73 hr. The temporal results indicate that 2S 0114+ 650 is the slowest neutron star rotator presently known. Spectral analysis reveals parameters typical of a high-mass X-ray binary system having an absorbed power law with an index of about 1.3 with a high-energy cutoff at approximately 8 keV. The introduction of a fluorescent iron line at 6.4 keV allowed better spectral fits, particularly during low states of emission. We have also determined that the intensity of 2S 0114+650 is strongly attenuated during part of the orbit, which makes it a member of the small class of eclipsing massive X-ray binaries.