8 Conclusions

Our spectroscopic analysis of QZ Car yielded valuable new information about the nature of this complicated multiple system being composed of two binary systems. We present refinements of the 20 day SB1 binary orbit, preliminary results on the short-period eclipsing binary, as well as a discussion of the long-term mutual orbit of both binaries. The orbital elements we found for the non-eclipsing system do not differ much from previous studies. The appearance and behaviour of lines of the eclipsing binary components can only be explained by the assumption that their equivalent widths are variable. In our case, the line disentangling was affected by an unfortunate CCD defect and by the superposition of the O II 4925 line on the profile of the crucial He I 4922 line. The mass function suggests that the invisible eclipsing binary component is more massive than its companion; hence it can be anticipated that this star will eventually be identified in high quality spectra.

Some conclusion about the mutual orbit of both binaries were reached. This orbit possesses a period of several decades, and it is demonstrated that it will be worth to further follow its evolution by evaluation of the light-time effect and probably also by speckle interferometry. A highly accurate distance will be found by a combination of these methods in the future. In this respect, the system is similar to SZ Cam (Mayer et al. 1994, Lorenz et al. 1998, Harries et al. 1998) and V505 Sgr (Mayer 1997; Ibanoglu et al. 2000).

Acknowledgements

The authors are indebted to Dr. Stickland for providing them a preliminary version of his study of QZ Car.