Chandra observation of the Big Dipper X 1624-490

We present the results of a 73 ks long Chandra observation of the dipping source X 1624 - 490. During the observation a complex dip lasting 4 h is observed. We analyse the persistent emission detecting, for the first time in the 1st-order spectra of X 1624 - 490, an absorption line associated to Ca XX We confirm the presence of the Fe XXV K-alpha and Fe XXVI K-alpha absorption lines with a larger accuracy with respect to a previous XMM observation. Assuming that the line widths are due to a bulk motion or a turbulence associated to the coronal activity, we estimate that the lines have been produced in a photoionized absorber between the coronal radius and the outer edge of the accretion disk.