  In an effort to determine the orbital period of the star DI Cru, we made
photometric and spectroscopic observations of this object between 1996 and
2002. The star is highly variable on short (few hours) as well as on long (few
months) time-scales. The optical spectrum is rich in strong emission lines of
high ionization species. Temporal Variance Spectrum - TVS - analysis shows that
the He II 4686A line has P Cyg-like variable absorption, while NV 4603/19A
lines have a strong and broad variable component due to the continuum
fluorescence from a source (stellar atmosphere/optically thick wind) of
variable temperature. We also show that the object has variable degree of
ionization, probably caused by wind density variation. The star presents
multiple periods in radial velocity and photometry. We derived, from our data,
a main radial velocity period of 0.3319 d with an amplitude of K = 58 km/s.
When at intermediate brightness level, this period is also seen in the
photometric measurements. When the star is at bright phase, the photometric
variations do not present the same period. Photometric periods ranging from
0.154 to 0.378 d are present, consistent with observations reported by other
authors. Besides the 0.3319 d period other spectroscopic periods are also seen.
On distinct epochs, the periods are different; Marchenko et al. (2000)
interpreted the 0.3319 d period as the orbital one. Although we do not discard
this possibility, the true binary nature (e.g. long term coherence or detection
of a secondary star) has not yet been demonstrated. DI Cru is a Population I WR
object. Given the similarities (e.g. multiple periods likely due to non-radial
oscillations), it could be interpreted as a luminous counterpart of the qWR
star HD 45166.
