  We report on two XMM-Newton observations of the low-mass X-ray binary X
1254-690. During an XMM-Newton observation of the low-mass X-ray binary in 2001
January a deep X-ray dip was seen while in a second observation one year later
no dips were evident. The 0.5-10 keV EPIC spectra from both non-dipping
intervals are very similar being modeled by a disk-blackbody and a power-law
continuum with additional structure around 1 keV and narrow absorption features
at 7.0 keV and 8.2 keV which are identified with the K alpha and K beta
absorption lines of Fe XXVI. The low-energy structure may be modeled as a 175
eV (sigma) wide emission line at ~0.95 keV. This feature is probably the same
structure that was modeled as an absorption edge in an earlier BeppoSAX
observation. The absorption line properties show no obvious dependence on
orbital phase and are similar in both observations suggesting that the
occurrence of such features is not directly related to the presence of dipping
activity. Narrow Fe absorption features have been observed from the two
superluminal jet sources GRO J1655-40 and GRS 1915+105, and the four low-mass
X-ray binaries GX 13+1, MXB 1658-298, X 1624-490 and X 1254-690. Since the
latter 3 sources are dipping sources, which are systems viewed close to the
accretion disk plane, and the two microquasars are thought to be viewed at an
inclination of ~70 degrees, this suggests that these features are more
prominent when viewed at high-inclination angles. This, together with the lack
of any orbital dependence, implies a cylindrical geometry for the absorbing
material.

Astrophysics