8. True distance of the nova
The discussion of the mechanism of ejection of nova shell has only small influence on the determination of the distance of Nova V 1974 Cygni. In view of the kinematic model presented above we can substantially revise the determination of the distance to the nova as inferred from the angular diameter measurements. The results are summarized in Table 10. The revised distances are remarkably similar and close to the values determined by standard methods (see Table 1).
Table 10. Rediscussion of the results derived from angular radii of the nova shell
It should be noted that there exists another rather independent method of the distance determination based on the knowledge of the visual interstellar extinction in the direction of the nova (l = 89 5, b = +7 8). The survey by Neckel & Klare (1980) gives = 0.56 mag kpc-1 (see also Andrillat & Houziaux 1993). Chochol et al. (1993) determined total = 0.99 mag and this leads to the distance d = 1.77 kpc, independent of the value of maximum absolute magnitude of the nova.
In conclusion, we are now convinced that the distances of Nova V 1974 Cyg derived by all reliable methods are in excellent mutual agreement (see the mean values in Tables 1, 9, 10 and value mentioned above), amounting to the average d = (1.77 0.11) kpc in full agreement with the distance of nova published by Chochol et al. (1993).
© European Southern Observatory (ESO) 1997
Online publication: July 3, 1998