Unraveling the Helix Nebula: Its Structure and Knots* **

@article{ODell2004UnravelingTH,
  title={Unraveling the Helix Nebula: Its Structure and Knots* **},
  author={C. O’Dell and P. McCullough and M. Meixner},
  journal={The Astronomical Journal},
  year={2004},
  volume={128},
  pages={2339-2356}
}
Through Hubble Space Telescope (HST) imaging of the inner part of the main ring of the Helix Nebula, together with CTIO 4 m images of the fainter outer parts, we have a view of unprecedented quality of the nearest bright planetary nebula. These images have allowed us to determine that the main ring of the nebula is composed of an inner disk of about 499'' diameter (0.52 pc) surrounded by an outer ring (in reality a torus) of 742'' diameter (0.77 pc) whose plane is highly inclined to the plane… Expand
The Multitude of Molecular Hydrogen Knots in the Helix Nebula
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The Molecular Envelope of the Helix Nebula
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PHOTOEVAPORATING FLOWS FROM THE COMETARY KNOTS IN THE HELIX NEBULA (NGC 7293) a a PARTIALLY BASED ON OBSERVATIONS MADE WITH THE NASA/ESA HUBB LE SPACE TELESCOPE, OBTAINED FROM THE DATA ARCHIVE AT THE SPACE TELESCOPE SCIENCE INSTITUTE.
We explain the Hα emission of the cometary knots in the Helix Nebula (NGC 7293) with an analytical model that describes the emission of the head of the globules as a photoevaporated flow produced byExpand
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We report high-resolution imaging of a prominent cometary globule in the Helix Nebula in the CO J = 1-0 (2.6 mm) and H2 v = 1-0 S(1) (2.12 μm) lines. The observations confirm that globules consist ofExpand
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