Preface
After more than two decades of intensive work, understanding the complex shapes of planetary nebulae and their implication on stellar evolution in general, is still a challenging and exciting goal. This was the fourth meeting of the Asymmetrical Planetary Nebulae (APN) conferences series devoted to this astrophysical problem. It was held from June 18 to 22, 2007, on La Palma in the Canary Islands (Spain).
APN4 was jointly organized by the Isaac Newton Group of Telescopes and the Instituto de Astrofisica de Canarias, and has greatly benefited from the generous contribution of the Nordic Optical Telescope, the Excelentisimo Cabildo Insular de la Palma (Island Government), its Patronato de Turismo (Tourist Board), and the Spanish Ministerio de Educacion y Ciencia via its funding programme Acciones Complementarias.
The staff of the Hotel H10 Taburiente Playa, where the conference was held, did as usual a very professional job permitting the smooth running of all conference events. A special vote of thanks goes to all members of the Scientific and Local Organizing Committees (SOC and LOC) and of the Local Support Team for their terrific effort in the preparation and development of the conference. We specially thank Pierre Leisy and Peter Sorensen for the help in the preparation of this book.
Sadly, a few months before APN4 our colleague Hugo E. Schwarz tragically died in a motorbike accident in La Serena, Chile. To honour the very significant contribution of Hugo to the field, and his friendship with many of us, we want to dedicate APN4 to his memory.
This book, hosted in the conference web page, contains 100 contributions from talks and posters presented during APN4. It is only published in electronic form, which provides a modern, cheaper, environmentally friendly, and flexible medium (a large number of colour pictures are included in the book). I hope that these contributions will serve as a reference and as a source of motivation to continue our search for the - still elusive - causes of the formation of the suprising but significant morphologies displayed by Planetary Nebulae. In this respect, we are already looking forward to Asymmetrical Planetary Nebulae V, which will be held in the Lake District in the United Kingdom from June 20 to 25, 2010. The conference organizing machine is at work, see the APN5 webpage. Stay posted, and...see you there!
La Palma, 31/01/2009
Romano L.M. Corradi, Arturo Manchado and Noam Soker