We report on the spectral analysis of the peculiar source Cir X–1 observed by the BeppoSAX satellite when the X–ray source was near the periastron .
A flare lasting \sim 6 \times 10 ^ { 3 } s is present at the beginning of the observation .
The luminosity during the persistent emission is 1 \times 10 ^ { 38 } erg s ^ { -1 } , while during the flare is 2 \times 10 ^ { 38 } erg s ^ { -1 } .
We produced broad band ( 0.1–100 keV ) energy spectra during the flare and the persistent emission .
At low energies the continuum is well fitted by a model consisting of Comptonization of soft photons , with a temperature of \sim 0.4 keV , by electrons at a temperature of \sim 1 keV .
Out of the flare a power-law component , with photon index \sim 3 , is dominant at energies higher than 10 keV .
This component contributes to \sim 4 \% of the total luminosity .
During the flare its addition is not statistically significant .
An absorption edge at \sim 8.4 keV , with optical depth \sim 1 , corresponding to the K-edge of Fe XXIII–XXV , and an iron emission line at 6.7 keV are also present .
The iron line energy is in agreement with the ionization level of the absorption edge .
The hydrogen column deduced from the absorption edge is \sim 10 ^ { 24 } cm ^ { -2 } , two order of magnitude larger than the absorption measured in this source .
We calculated the radius of the region originating the comptonized seed photons , R _ { W } \sim 150 km .
We propose a scenario where R _ { W } is the inner disk radius , a highly ionized torus surrounds the accretion disk and a magnetosphere is large up to R _ { W } .
The absorption edge and the emission line could originate in the photoionized torus , while the comptonized component originates in an inner region of the disk .