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| Paper: |
Correlation of PN Morphologies and Nebular Parameters |
| Volume: |
313, Asymmetrical Planetary Nebulae III |
| Page: |
3 |
| Authors: |
Manchado, A. |
| Abstract: |
A study of the correlation of the morphology of a complete sample of 255
galactic planetary nebulae (PNe) with their nebular parameters is
presented here. Projection effects were taken into account. PNe were
classified according to the following scheme: round (R, 25%), elliptical
(E, 58% of the sample), and bipolar (B, 17%). Bipolars include the
quadrupolar subsample. A subclass of pointsymmetric and multiple shell
PNe was also found. Nine per cent of ellipticals and 46% of bipolars
were found to be pointsymmetric. Thirty-five per cent of the round and
22% of the elliptical PNe were found to be multiple shell PNe (MSPNe).
Galactic latitude was found to be different for each morphological class
(|b| = 8°, 5° and 2° for types R, E, and B, respectively).
Galactic height was also found to vary: < z > = 647, 276, and 100
pc for categories R, E, and B, respectively. Segregation according to
the chemical abundances was also found, with helium abundances of 0.10,
0.12, and 0.14 and N/O of 0.21, 0.31, and 1.33 for types R, E, and B,
respectively. Both galactic distribution and chemical abundances point
to a different stellar population for each morphological class, the
round and bipolar types being the result of low and high stellar mass
progenitor evolution, respectively. |
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