Planetary Nebulae: A Study of Morphology
With the advent of increasingly sensitive telescopes and detection instruments in the 20th century, most notably the Hubble Space Telescope, new observable structures and morphologies have revolutionized the study of planetary nebulae. Previously thought to be the result of the simple, isotropic exhaustion of envelope material at the end of the nuclear-burning lifetime of a star, new complicated models are under investigation to explain the many asymmetries and anomalous features that have been detected. The effects of strong magnetic fields in rapidly rotating stars, binary companions and accretion disk structures represent some of the most successful explanations. However, many of these theories lack observational evidence or physical justifications, and so there are many open questions left to be answered. In my presentation, I will first discuss the formation of planetary nebulae and assess the relevance of select models.