A hard tail in the broadband spectrum of the dipper XB 1254-690

We report on the results of spectral analysis of the dipping source XB 1254 -690 observed by the BeppoSAX satellite. We find that the X-ray dips are no t present during the BeppoSAX observation, in line with recent RXTE results . The broadband (0.1-100 keV) energy spectrum is well fitted by a three-com ponent model consisting of a multicolor disk blackbody with an inner disk t emperature of similar to0.85 keV, a Comptonized spectrum with an electron t emperature of similar to2 keV, and bremsstrahlung at a temperature of simil ar to 20 keV. Adopting a distance of 10 kpc and taking into account a spect ral hardening factor of similar to1.7 (because of electron scattering which modifies the blackbody spectrum emitted by the disk), we estimated that th e inner disk radius is R-in(cos i)(1/2) similar to 11 km, where i is the in clination angle of the system with respect to the line of sight. The Compto nized component could originate in a spherical corona or boundary layer, su rrounding the neutron star, with optical depth similar to 19. The bremsstra hlung emission, contributing similar to4% of the total luminosity, probably originates in an extended accretion disk corona with radius similar to 10( 10) cm. In this scenario, we calculated that the optical depth of this regi on is similar to0.71 and its mean electron density is N-e similar to 2.7 x 10(14) cm(-3). This last component might also be present in other low- mass X-ray binaries, but, because of its low intrinsic luminosity, it is not ea sily observable. We also find an absorption edge at similar to1.27 keV with an optical depth of similar to0.15. Its energy could correspond to the L e dge of Fe XVII or K edge of Ne X or neutral Mg.