BeppoSAX detection of a cyclotron feature in the spectrum of Cen X-3

The High Mass X-ray Binary Pulsar Centaurus X-3 was observed by the BeppoSA X satellite during 1997 February 17, while the system was in a high-luminos ity (L-x = 4.3 . 10(37) erg s(-1)) post-egress state. In this Letter we rep ort the detection of an absorption-like feature, centered at similar to 28 keV, in the broad band phase averaged spectrum. Interpreting the feature as due to cyclotron resonant scattering, we estimate the magnetic field stren gth close to the surface of the neutron star to be B similar to (2.4 - 3.0) . 10(12) G.