Stefan Kimeswenger, Institute of Astrophysics,
University Innsbruck, Austria
The central star V4334 Sgr (Sakurai's `Nova') of the planetary nebula PNG010.4+04.4 underwent in 1995-1996 the rare event of a very late helium flash burning. It is one of only two such events to have occurred in the era of modern astronomy (the other was V605 Aql = Nova Aql 1919). All the other prominent objects originated from events which occurred several thousand years ago (e.g. A30, A78). Thus it is of special interest for stellar evolution theory to model the observations which we have obtained during recent years. These models essentially depend on the basic stellar parameters like the effective temperature, surface gravity and the stellar radius; most of them strongly depend on the assumed distance of the object. Some models may give some constraints on this parameter, but most of them depend on the assumption as input parameter. Thus it is of special interest to fix the distance to this object, either by means of model-independent methods, or by combining lower and upper limits given by physical constraints obtained from models. I compare here the available methods for the distance determination and discuss the divergent results.