The evolution of planetary nebulae. III - Position-velocity images of butterfly-type nebulae
Citations Over TimeTop 18% of 1989 papers
Abstract
Observations of the motions of the shells of the planetary nebulae NGC 2346, NGC 2371-2, NGC 2440, NGC 6058, NGC 6210, IC 1747, IC 5217, J-320, and M2-9 are presented. These are all 'butterfly' type PNs, and show evidence for bipolar shocks. The observations are interpreted in terms of a fast spherical wind, driven by the central star into a quasi-toroidal envelope deposited earlier by the star, during its slow-wind phase on the asymptotic giant branch. It is shown that this model, which is a straightforward extension of a mechanism previously invoked to account for elliptical PNs, reproduces the essential kinematic features of butterfly PNs. It is inferred that the envelopes of butterflies must have a considerable equator-to-pole density gradient, and it is suggested that the origin of this asphericity must be sought in an as yet unknown mechanism during the AGB, Mira, or OH/IR phases of late stellar evolution.
Related Papers
- Madama Butterfly or M. Butterfly？ An Analysis on Imperfection of Deconstruction in M. Butterfly(2015)
- Study on the resources of butterfly in southwest Hunan province(2002)
- → Long Butterfly Spread Basics(2012)
- Susquehanna Chorale Spring Concert "Roots and Wings"(2017)
- → A selection of the final butterfly designs(2017)