dc.contributor.advisor O'Dell, C. Robert Handron, Kerry Dorinda Patrick 2009-06-04T08:39:20Z 2009-06-04T08:39:20Z 1996 https://hdl.handle.net/1911/17047 The central star of the Helix Nebula, the closest planetary nebula, is ringed by hundreds of Cometary Knots. Presented here are images taken with WFPC2 of a field in the northern portion of the bright ring and some physical parameters and models derived from the data. The field of view contains more than thirty well formed Cometary Knots and reveals that the entire bright ring is composed of knot-like structures. The data is in three narrow emission line filters, H$\alpha$, (OIII) and (NII). Optical thickness to ionizing photons for the knots is established, physical properties such as density in the ionized portions of the knots and dust mass are determined and the beginning of a model to explain the detailed structure set forth. 45 p. application/pdf eng AstronomyAstrophysics Cometary knots in the Helix Nebula Thesis Text Physics Natural Sciences Rice University Masters Master of Science Handron, Kerry Dorinda Patrick. "Cometary knots in the Helix Nebula." (1996) Master’s Thesis, Rice University. https://hdl.handle.net/1911/17047.
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