The central star V4334 Sgr ( Sakurai ’ s Nova ) of the planetary nebula PN G010.4+04.4 underwent in 1995-1996 the rare event of a very late helium flash .
It represents only one out of two such events during the era of modern astronomy ( the second event was V605 Aql = Nova Aql 1919 ) .
All the other prominent objects of that type originate from events occurring several thousands of years ago ( e.g .
A30 , A78 ) .
Thus it is of special interest for stellar evolution theory to model the detailed observations obtained during the last four years .
Those models depend essentially on basic stellar parameters like effective temperature , surface gravity and stellar radius .
Most of them depend strongly on the assumed distance to the object .
Some models may give some constraints on this parameter , but most of them depend on the assumption as input parameter .
Hence to determine a relyable distance is of considerable significance .
This should be obtained through models that give us lower and upper boundaries , or through means which are independent of models . The detailed review , by using every kind of determination available up to now , leads to a galactic foreground extinction of E _ { B - V } = 0 ^ { m } . 75 _ { \pm 0.05 } and a distance of D = 2.0 _ { -0.6 } ^ { +1.0 } kpc .