lAD Symposium No. 66 was held in Warsaw from September 10th to September 12th 1973, in connection with the Extraordinary General Assembly of the lAD. It was arranged by lAD Symposium No. 35 and the Scientific Organising Committee con­ sisted of A. G. Massevitch (Chairman), A. V. Tutukov (Secretary), H. M. van Horn, N. Dallaporta, J. P. Ostriker, B. Paczynski, G. Ruben, E. Schatzman, R. J. Tayler and A. Weigert. This volume contains the full texts of all of the invited papers presented at the Symposium, apart from that delivered by R. P. Kraft, which is published in abstract because it is appearing in full elsewhere. In addition the short communications given at the Symposium are published in abstract. I attempted to take down all of the dis­ cussion as it occurred and all contributors to the discussion were asked to provide copies of their remarks. From these sources an edited version of the discussion has been produced. As the final version has not been seen by the contributors, I should be held responsible for all errors. At Warsaw, some of the short communications did not immediately follow the invited paper to which they referred. In the printed version they and any discussion relating to them are placed in the most logical position. A small number of short communications, which were circulated in abstract at Warsaw but which were not delivered orally, are also included in the published version.

Inhalt

Nuclear Reactions and Neutrinos in Stellar Evolution.- Screening Factors in Late Stellar Evolution.- The Explosive r-Process.- Hot CNO-Ne Cycles.- Discussion Following Paper by Arnett.- Circulation and Mixing.- On the Mixing of the Matter in Semiconvective Regions of Massive Stars.- Discussion Following Paper by Kippenhahn.- Non-Explosive Mass Loss.- Mass Ejection by Radiation Pressure.- Stellar Envelopes at Supercritical Luminosity.- Discussion Following Paper by Woolf.- Review of IAU Symposium No. 59 on Stellar Instability and Evolution, Canberra, August 1973.- Discussion Following Paper by Iben.- Evolution of Stars with M?8M?.- The URCA Process in Convective Cores.- Discussion Following Paper by Paczynski.- Evolution of Stars with M?8M?.- Stability Properties of Stars with Central He Burning.- The Effect of Changing the Initial Chemical Composition on the Evolution of a 20 M? Star.- Evolution of Massive Close Binaries.- On the Evolutionary Stage of V448 Cyg.- The Investigation of Open Clusters by Means of Theoretical HR-Diagrams.- Integral Parameters and the Total Mass of Open Clusters.- Mass Loss from Stars and the Location of Blue Supergiants in the HR Diagram.- Supergiant Stars as Chemical Composition Indicators.- Discussion after Paper by Massevitch.- Mixing Between the Core and the Envelope in Stars with Deep Convection Zones.- Evolutionary Abundance Changes in the Envelopes of Moderate Mass Red Supergiants.- Surface Abundances Resulting from Deep Mixing.- Mixing in Stars.- Interpretation of Carbon Stars.- Discussion after Paper by Sugimoto.- Presupernovae.- Do Pulsars Make Supernovae?.- Evolution of Massive Stars from Helium Burning to the Start of Neutronization.- On the Final Fate of Differentially Rotating Degenerate Configurations.- The Explosion of a Rotating Magnetized Star as a Supernova.- Iron Core Collapse in 10 to 30 M? Stars and the Effect of ? Neutrinos.- Discussion after Paper by Nadyozhin.- The Theory of Novae and Nova-Like Systems.- Possible Progenitors of Some Nova-Like Variables.- Discussion after Paper by Faulkner.- Observational Data on Novae and Supernovae.- Early Photographic Observations of Red and Infrared Features in the Spectrum of SN 1972e.- The Reliability of Photometric and Spectroscopic Data of Novae.- On the Frequencies of Type I and Type II Supernovae.- Contracting Envelopes of Novae after Outbursts.- On the Peculiarities of the Star Listed as Nova Aurigae 1960-64 (KR Aur).- Evidence for Continued Ejection Models of Novae.- A Note on the Possible Evolutionary Status of the Recurrent Nova T CrB.- Discussion after Paper by Mustel.- The Chemical Composition of Late Type Stars.- Abundances in Ap Stars; Result of Magnetic Binary Evolution.- Helium Abundance from Radio Recombination Lines.- Discussion after Paper by Boyarchuk.- FG Sagittae: The s-Process Episode (Abstract).- Deciphering FG Sagittae.- Discussion after Paper by Kraft.- Nuclei of Planetary Nebulae.- Discussion after Paper by O'Dell.- White Dwarfs.- The Sources of Energy in White Dwarfs.- Degenerate Dwarfs with Liquefying Cores.- Evidence for g-Mode Oscillations in the Peculiar Blue Variable CD ?42° 14462.- Circulation in Differentially Rotating White Dwarfs.- Discussion after Paper by Vila.- Horizontal Branch Stars (Edited Version of I. Iben's Remarks).- Four-Color Observations of Blue Horizontal-Branch Stars.- On the Behaviour of Globular Cluster Red Giants in the Colar-Magnitude Diagram.- Photometric Behaviour of Field RR Lyrae Stars.- What SNU? The Case of the Missing Solar Neutrinos.- The Interior Structure of the Sun as Gleaned from the Various Explanations of the Null Solar Neutrino Experiment Results.- Effect of Magnetic Field on Solar Neutrino Flux.- Praesepe: No Evidence for Solar Mixing.- A Listener's Digest of IAU Symposium No. 64 on Gravitational Radiation and Gravitational Collapse.- General Discussion.- Concluding Remarks.- Object Index.- Author Index.