Results of a 1997 September 9–10 BeppoSAX observation of the 5.57 hr low-mass X-ray binary ( LMXRB ) X 1822-371 are presented .
The 0.3–40 keV spectrum is unusually complex and can not be fit by any of the standard models applied to other LMXRB .
At least two components are required .
One component has a shape consistent with that expected from the Comptonization of an input soft ( Wien ) spectrum while the other , contributing \mathrel { \hbox { \hbox to 0.0 pt { \lower 2.365 pt \hbox { $ \sim$ } } \kern - 3.0 pt \raise 1.72 pt \hbox { $ > $ } } } 40 % of the 1–10 keV flux , is consistent with being a blackbody .
In addition , there is a “ dip ” in the spectrum which can be modeled by a 1.33 \pm ^ { 0.05 } _ { 0.11 } keV absorption edge with an optical depth , \tau , of 0.28 \pm 0.06 .
If the same model is fit to ASCA Solid-State Imaging Spectrometer spectra obtained in 1993 and 1996 , then reasonable fits are also obtained , with a similar absorption feature required .
The nature of this feature is highly uncertain ; its energy corresponds to the K-edges of highly ionized Ne x and neutral Mg , or to an L-edge of moderately ionized Fe .
Surprisingly , no strong ( \tau > 0.05 ) Fe-K or ( \tau > 0.18 ) O-K edges are visible .
The folded lightcurve of X 1822-371 is similar to previous observations , except that no strong softening is seen near the eclipse .
An updated orbital ephemeris is provided .