LOW-ENERGY LINE EMISSION FROM CYGNUS X-2 OBSERVED WITH THE BEPPOSAX LECS

We present a 0.2-10 keV spectrum of the low-mass X-ray binary Cygnus X -2 obtained using the Low Energy Concentrator Spectrometer on-board Be ppoSAX. The spectrum can be described by a cut-off power-law model wit h absorption of (2.28+/-0.07) x 10(21) atoms cm(-2), a power-law index of 0.78+/-0.02 and a cut-off energy of 4.30+/-0.08 keV (68% confidenc e errors), except at energies near similar to 1 keV where excess emiss ion is present. This can be modeled by a broad Gaussian line feature w ith an energy of 1.02+/-0.04 keV, a full width half-maximum of 0.47+/- 0.07 keV and an equivalent width of 74+/-(25)(11) eV. This result conf irms earlier reports of line emission near 1 keV and shows the intensi ty and structure of the feature to be variable.