4U 1822 - 371 is one of the proto-type accretion disk coronal sources with an orbital period of about 5.6 hours .
The binary is viewed almost edge-on at a high inclination angle of 83 degrees , which makes it a unique candidate to study binary orbital and accretion disk dynamics in high powered X-ray sources .
We observed the X-ray source in 4U 1822 - 371 with the Chandra High Energy Transmission Grating Spectrometer ( HETGS ) for almost nine binary orbits .
X-ray eclipse times provide an update of the orbital ephemeris .
We find that our result follows the quadratic function implied by previous observations ; however , it suggests a flatter trend .
Detailed line dynamics also confirm a previous suggestion that the observed photo-ionized line emission originates from a confined region in the outer edge of the accretion disk near the hot spot .
Line properties allow us to impose limits on the size of accretion disk , the central corona , and the emission region .
The photo-ionized plasma is consistent with ionization parameters of log \xi > 2 , and when combined with disk size and reasonable assumptions for the plasma density , this suggests illuminating disk luminosities which are over an order of magnitude higher than what is actually observed .
That is , we do not directly observe the central emitting X-ray source .
The spectral continua are best fit by a flat power law with a high energy cut-off and partial covering absorption ( N _ { H } ranging from 5.4– 6.3 \times 10 ^ { 22 } { cm } ^ { -2 } ) with a covering fraction of about 50 \% .
We discuss some implications of our findings with respect to the photo-ionized line emission for the basic properties of the X-ray source .