A&A Supplement Series, Vol. 125, October II 1997, 355-366
Received February 23, 1996; accepted January 13, 1997
C.T. Hua
Laboratoire d'Astronomie Spatiale du CNRS, Allée Peiresc, Traverse du Siphon, 13012 Marseille, France
Deep narrow band interference filters observations are presented for 7 type
I galactic planetary nebulae (PNe). Except for the nearly circular planetary
nebula A 39, the observations show overall dimensions appreciably larger than
those quoted so far. The observed PN (NGC 6302 excepted) could have linear
diameters larger than 1 pc. Our new observations imply ionized masses often
larger than 
, suggesting that much of the mass ejected by the
PN precursor is contained in faint outer extensions. This might contribute
to the solution of the "mass deficit" in PNe. We have also provided
calibrated fluxes for some specific emission lines. In spite of their
apparent morphological differences, our observations suggest that these
type I PNe possess the same intrinsic structure as that displayed by NGC
650-1, the Ring Nebula, and even Sh 1-89 with its elongated jet-like
feature, but viewed under different angles.
keywords: planetary nebulae