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Astron. Astrophys. 337, 253-260 (1998)

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6. Conclusions

We have presented the HIPPARCOS space-borne measurements for a sample of 19 planetary nebulae.

An important conclusion concerns the distance scale. All the previously known distances of each target in this small sample look overestimated when we trust the HIPPARCOS trigonometric parallaxes.

For very compact nebulae, the HIPPARCOS parallax measurement could be biased by the motion of the nebula; in particular, the very small distances given by HIPPARCOS for Sw St 1 and Hu 2-1 are not trustworthy.

The position on the HR-diagram is not significantly different from previous studies, excepting PHL 932 and SaSt 2-12.

Additional analysis of the proper motion constrains the orbital parameters of the binary nucleus of A 35, which seems to be a wide system.

Asymmetric morphology of some PN is related to the transverse velocity direction.

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© European Southern Observatory (ESO) 1998

Online publication: August 6, 1998