  We report the discovery of narrow X-ray absorption features from the two
dipping low-mass X-ray binary 4U 1916-053 and X 1254-690 during XMM-Newton
observations. The features detected are identified with resonant scattering
absorption lines of highly ionized iron (Fe XXV and Fe XXVI). Resonant
absorption features are now observed in a growing number of low-mass X-ray
binaries (LMXBs): the two superluminal jet sources GRS 1915+105 and GRO
J1655-40, the bright LMXB GX 13+1 and the four dipping sources MXB 1658-298, X
1624-490, 4U 1916-053 and X 1254-690. The early hypothesis that their origin
could be related to the presence of superluminal jets is thus ruled out.
Ionized absorption features may be common characteristics of accreting systems.
Furthermore, their presence may depend on viewing angle, as suggested by their
detection in dippers which are viewed close to the disk plane, and by the fact
that GRS 1915+105, GRO J1655-40 and GX 13+1, although not dippers, are
suspected to be also viewed at high inclination.
