SIMBAD references

Photometric elements and apsidal motion parameters of the southern detached eclipsing binary AO Vel (HD 68826) have been determined from complete uvby light curves (Gronbech 1987; Paper I), and photometric observations for additional times of minimum included in this paper. The relative radii of the components are 0.214±0.006 and 0.193±0.006, respectively. The orbit is slightly eccentric, e=0.0761±0.0017, and shows apsidal motion with a short period of U=56.8±1.9yr. Small asymmetries are present in the v, b and y light curves, whereas significant effects are seen in u, causing the results from this band to be unreliable. Inhomogeneities like e.g. spots may be present on (one of) the stellar surfaces. A third component is member of the system. It has a wide orbit of a sini=7.0±1.0AU; the orbital period is 25.6±2.5yr. Its contribution to the total light is about 30% and its luminosity thereby between those of the eclipsing components. AO Vel is located within the field of Cr 173, but we find it too faint for membership. Only rough estimates of the absolute dimensions of the components can be given (Sect. 5), since radial velocity observations are not yet available. We strongly recommend that such data - as well as high resolution spectra for abundance analyses - are obtained, mainly because AO Vel is mentioned as one of the 3-5 known Ap eclipsing binaries and furthermore the only example of the Si-type.