)
for the system. A polarimetric study by Luna (1988) constrained the inclination of the orbit between
and
,
with a preferred value of
.
The study of the light curve of HD152248 by Mayer et al. (1992) revealed that the system displays two eclipses of unequal depth and that both minima are not separated by a 0.5 cycle, suggesting a non-zero eccentricity. Based on IUE observations and using a cross-correlation technique, Stickland et al. (1996, ST96 hereafter) derived a period of 5.816083 days, an eccentricity of 0.124 and a mass ratio of 0.941. The deepest eclipse corresponds to the occultation of the less-massive component. In order to avoid confusion, we choose to adopt the convention of ST96 for the primary and secondary. In the following, we will thus refer to the component occulted during the deepest (i.e. primary) eclipse as the primary star of the system.
Based on the same set of IUE data and using a tomographic reconstruction algorithm to separate primary and secondary spectra, Penny et al. (1999, PGB hereafter) derived a spectral type of O7I+O7I. They also re-analysed the light curve of the system, complementing the Mayer et al. (1992) data set with Hipparcos observations. PGB showed that the system displays ellipsoidal light variations due to tidal deformations. They derived an inclination of
for the orbit of the system and polar radii of
and
for the primary and secondary respectively. Combining spectroscopic and photometric results, they computed masses of
and
.
Howarth et al. (1997) reported that HD152248 is displaying the Struve-Sahade effect, i.e. that the secondary lines seem to be stronger when the secondary is approaching. However, this result was not confirmed by PGB, who found no evidence for this effect in the strength of the cross-correlation function of the IUE spectra of HD152248 with their standard star, HD34078.
Copyright ESO 2001