In the centennial year, 1985-86, of Harlow Shapley's birth, the study of globular clusters was no less important to the development of astronomy than in 1915, when Shapley first noted their concentration on the sky. By 1917 Shapley had used the properties of the system of globular clusters to complete the Copernican revolution and locate the solar system, and its Earth-bound observers, far from the center of the Galaxy and the globular cluster distribution. Seven decades later, in the year of these proceedings, globular cluster research and the study of the system of globular clusters in our own and distant galaxies is undergoing a renaissance of activity. The introduction of new observational tools, particularly CCD imagers and digital spectrographs, as well as powerful theoretical methods have transformed the study of globular clusters into one of the main line areas of modern astrophysics. Thus it seemed particularly appropriate to one of us, when considering how the Harvard College Observatory might mark the Shapley centennial, to propose and plan for an IAU Symposium on Globular Cluster Systems in Galaxies. Planning for the Shapley Symposium, as it came to be called, was even more drawn out than the preparation of this volume. The Symposium was originally proposed to the IAU Secretariat in time for it to be held in August, 1985, so that it might occur in the centennial (calendar) year.

Proceedings of the 132nd Symposium of the International Astronomical Union, held in Paris, France, June 29-July 3, 1987

Gaseous nebulae offer outstanding opportunities to atomic physicists, spectroscopists, plasma experts, and to observers and theoreticians alike for the study of attenuated ionized gases. These nebulae are often dusty, heated by radiation fields and by shocks. They are short-lived phenomena on the scale of a stellar lifetime, but their chemical compositions and internal kinematics may give important clues to advanced stages of stellar evolution. The material herein presented is based on lectures given at the University of Michigan, University of Queensland, University of California, Los Angeles, and in more abbreviated form at the Raman Institute, at the Scuola Internazionale di Trieste, and elsewhere. Much of it is derived origionally from the series "Physical Processes in Gaseous Nebulae" initiated at the Harvard College Observatory in the late 1930s. I have tried to emphasize the basic physics of the mechanisms involved and mention some of the uncertainties that underlie calculations of many basic parameters. Emphasis is placed on ionized plasmas with electron temperatures typically in the neighborhood of 10, OOOoK. Dust and other ingredients of the cold component of the interstellar medium are treated briefly from the point of view of their relation to hot plasmas of H II regions and planetaries. Chemical composition determinations for nebulae are discussed in some detail while the last section deals with interpretations of elemental abundances in the framework of stellar evolution and nucleogenesis. Gaseous nebulae offer some particularly engaging opportunities for studies of stellar evolution.

IAU Symposium 127 was held in Princeton on May 28-31, 1986, at the Institute for Advanced Study. There were 150 participants from 19 countries. This was the first IAU Symposium devoted exclusively to elliptical galaxies. The last decade has been a period of exceptionally rapid progress regard ing our understanding of elliptical galaxies, driven on the observational side by a wealth of new photometric and spectroscopic data, and on the theoretical side by the recognition that ellipticals are slowly rotating triaxial systems, instead of rotationally flattened bodies. The 30 invited speakers reviewed all aspects of this progress, its consequences, and the major outstanding problems. Nearly 80 poster contributions were displayed for the duration of the meeting. These contained many of the most recent developments. The first part of these Proceedings contains the written versions of the invited reviews and the summary, in the order of their presentation. The accompanying discussions are based on the written versions of questions and answers as handed in by the participants. The second part of this book is devoted to the poster contribu tions. They have been grouped in a thematic order, proceeding from morphology to theory. Indices of objects, subjects, and names are provided. Unfortunately, none of the invited participants from the USSR were able to attend the Symposium. The Proceedings include the written versions of the planned contributions by Popov and Polyachenko."

The objective of this meeting was to bring together collea gues from different branches of observational astronomy and theoretical astrophysics to discuss and analyse the rapid progress in our knowledge and understanding of the matter surrounding stars, streaming off stellar surfaces, or fall ing onto stars. The meeting was sponsored by IAU Commis sions 36 (Theory of Stellar Atmospheres), 29 (Stellar Spec tra), and 34 (Interstellar Matter). There were two special reasons for organizing this meeting at Heidelberg in 1986: During this year the University of Heidelberg celebrated its 600th anniversary and the IAU symposium joined the many scientific events accompanying this celebration. Secondly, the year 1986 also marked the conclusion of a special co operative research project ("Sonderforschungsbereich") in astrophysics at Heidelberg, a major part of which had been devoted to the physics of circumstellar matter. The main topics discussed at this meeting were: (1) circumstellar matter, bipolar flows, and jets from young stars and protostars; (2) circumstellar envelopes of evolved stars; (3) stellar coronae; (4) stellar winds from hot and cool stars; (5) dust formation and circumstellar chemistry. Many exciting new results were presented in 21 invited or review papers, 26 contributed papers, and 127 poster papers. This symposium would not have been possible without the generous financial assistance of the International Astronomical Union, the German Science Foundation (DFG), and the State Government of Baden-Wurttemberg. The practi cal support of the University of Heidelberq and the Max Planck-Society was also very valuable."

The idea for an international symposium on the interstellar medium was first discussed at the University of Wyoming during the summer of 1984. It was obvious that the outstanding natural beauty of the Teton mountain range in northwestern Wyoming must be matched by a meeting with the broadest appeal to the astronomical community. If the meeting was to produce a book, it must likewise be an important contribution to the astronomical literature. It was for these reasons that early in the discussions, it was decided that the University should host a "school." with the invited speakers presenting tutorials on a broad range of topics involving the interstellar medium. The symposium proceedings would then be a compilation of the written versions of these presentations. It has been nearly a decade since Lyman Spitzer published his classic text on the interstellar medium and we felt the need for a school and book that would focus on the recent developments in our understanding of the inter stellar medium. Thus, we view this two-volume set as an adjunct text to Spitzer's book."

IAU Symposium No. 121 was hosted by the Byurakan Astrophysical Observatory in Soviet Armenia, almost 30 years after Ambartsumian's pioneering ideas about galaxy activity were first published and almost exactly 20 years after the first Byurakan IAU symposium on nuclear activity (No. 29, "Non-stable Phenomena in Galaxies, May 1966). Although the proceedings of the first Byurakan symposium were not published in English, that conference provided a definitive impulse to the field, as Ambartsumian's ideas had done 10 years earlier. The Byurakan Astrophysical Observatory was thus a particularly appropriate setting for IAU 121. The symposium was also very timely since many new exciting results were presented which will surely revolutionize many of our present ideas about nuclear activity in galaxies and QSO's. The first results of the by now famous Markarian survey were presented by B.E. Markarian in the first Byurakan conference. Unfortunately, his untimely death prevented him from attending the second conference, but the influence of his fundamental work was certainly felt.

This is the first time that the International Astronomical Union has held a symposium on objects of totally unknown nature. In fact. M. Rees has pointed out that the mass of the individual particles that make up the dark matter is unknown to > 70 orders of magnitude. Since dark matter appears to make up ~ 90 % of the mass of the Universe. it presents us with one of the most fundamental problems in astrophysics. IAU Symposium 117 on Dark Matter in the Universe was held on June 24 - 28. 1985. Our hosts were Princeton University and the Institute for Advanced Study. which together form one of the most active centers of work on the dark matter problem. There were ~ 190 participants from 16 countries. These proceedings include the 31 review and invited papers. 72 of the 85 poster papers. and the two general discussions. The idea that the Universe might contain much more mass than we see in gas. stars and their remnants has been with us for over 50 years. In 1933. F. Zwicky pointed out that the Coma Cluster could be in equilibrium at the large observed velocity dispersion only if a great deal of unseen matter were present. However. in the absence of other evidence. the idea of "dark matter" was not widely pursued.

The chemical processes of formation and destruction of molecules have been found to be widespread in astronomical scenario. It occurs in comets, planetary atmospheres including ionospheres, early solar system, stellar atmospheres, circumstellar shells, interstellar clouds, and possibly even in the early universe. Physical conditions are naturally different in the different situations, but there is unity in the underlying physics and chemistry in this diversity. Therefore, a need was felt to gather together astronomers, physicists and chemists in these and allied interdisciplinary fields to enrich each other with their experiences. This International Astronomical Union Symposium No.120 on Astrochemistry, the proceedings of which is this, has partially fulfilled this need. This symposium, held at the beautiful and scenic sea resort of Goa, India, between December 3-7, 1985, under the sponsorship of the IAU Commission No.34 and co-sponsorship of IAU Commissions 14, 15, 29 and 36, was attended by 116 registered participants with 19 accompanied guests from 19 countries. The scientific programme comprised of 34 review talks, 15 invited talks and 47 contributed poster papers, clima xed by a grand finale by Professor A. Dalgarno with an overview of th whole symposium. The Symposium covered almost all aspects of astro chemistry from the early universe to comets and meteorites, except iono spheres and planetary atmospheres. Basic atomic and molecular physics, experimental and observational results, and theoretical calculations and modelling, all were stressed."

The idea to hold a Symposium on Star Forming Regions in Japan, be fore or after the New Delhi General Assembly of the IAU, originated in 1981. One of the main reasons was that the 45-m telescope was expected to be inoperationby 1982. In addition it was considered that Japan had been very active in the theory of star formation as well as in mm and IR observations of star forming regions. At the Patras General Assembly of the IAU the issue was brought up for discussion at meetings of Commis sions 34 (Interstellar Matter) and 40 (Radioastronomy), the former agreed to sponsor the Symposium, while the latter agreed to co-sponsore it. The IAU Executive Committee accepted the proposal to hold the Symposium on September 1983. The Symposium was held in Tokyo on 11-15 November 1985, just before the New Delhi General Assembly. It was attended by 250 scientists from 18 countries, and 212 papers were presented. The Scientific Organizing Committee elaborated a superb program of invited and review presentations. The Conference consisted of oral and poster sessions. The oral sessions included review papers, invited papers and a few of the contributed papers; after each presentation a discussion was held. The poster ses sions included most of the contributed papers and were very well attended. We consider that the scientific goals of the meeting were amply achieved and we express our thanks to all the participants and specially to the members of the SOC for making them possible."

Proceedings of the 116th Symposium of the International Astronomical Union, held at Porto Heli, Greece, May 26-31, 1985

IAU Symposium No. 111, "Calibration of Fundamental Stellar Quanti- ties", was held at Villa Olmo, Como, Italy, on May 24-29, 1984. Meet- ings held in the past ten years on related topics include: IAU Symposium No. 109, '*Astrometric Techniques", held at the University of Florida in Jan. , 1984, "The MK Process and Stellar Classification", held at the University of Toronto in June, 1983, "Stellar Absolute Energy Distri- butions", an unpublished Joint Meeting (Commissions 25 and 45), held at the General Assembly of the IAU in Patras, Greece in August, 1982, IAU Colloquium No. 62, "Current Techniques in Double and Multiple Star Re- search", held at Northern Arizona University in May, 1981, the ESO Work- fl shop: "Methods of Abundance Determination for Stars , held in Geneva in March, 1980, "Problems of Calibration of Multicolor Photometric Sys tems", held at Dudley Observatory in March, 1979, IAU Colloquium No. 48, "Modern Astrometry", held at the University of Vienna in Sept. , 1978, IAU Colloquium No. 50, "High Angular Resolution Stellar Interferometry" held at the University of Maryland in Aug. , 1978, "Spectral Classifice. - tion of the Future", held at the Vatican in July, 1978 and IAU Sympos- ium No. 72, "Abundance Effects in Classification", held at the Univer- sity of Lausanne in July, 1975. The present meeting was the first to cover the broad range of the calibration of fundamental stellar qU8T". ti- ties in one meeting. Nine commissions of the IAU co-sponsored the meeting.

The emphasis in these proceedings of lAD Symposium No. 113, Dynafrri-, ' s of Star Clusters. and.. .Le. mab rPIHlon for orZ'lnizinp: thE" symposium in the spring of 1984, was the rapid increase during the preceeding year in our understanding of core collapse. The last I.A.D. Symposium to discuss the dynamics of star clusters at length was No.69, Dynamics of Stellar Systems held in Besan on in 1974. For a few years afterwards, globular clusters receiveu much attention due to the discovery of X-ray bursters and the mounting evidence that X-ray sources in globular clusters were formed in completely different ways than those within our galaxy. Globular clusters, which until this time had a reputation for sedate old age, turned out to lead violent private lives at high energies. However, in the early 80's globular clusters seemed to lose some of the glamor of the 70's. The grand speculations of heavy black holes lurking in their centers had to make way for a variety of observational evidence which indicated that the X-ray sources are low-mass close binaries instead. But, though dynamical fashion turned to heavy galac tic halos and so on, some of the unsolved theoretical problems regard ing the evolution of star clusters kept their fascination for a number of relatively isolated workers. After several years of inconspicuous labor, a number of preprints suddenly appeared in the spring of 1983 that studied the evolution of globular clusters after core collapse."

In June 1983 the Astronomical Institute of the State University of Groningen, founded by Kapteyn about 100 years ago, celebrated its one-hundredth anniversary. At the suggestion of its Chairman, R.J. Allen, the Kapteyn Institute invited the International Astronomical Union to mark the centenary by holding a Symposium on "The Milky Way Galaxy". The purpose of the Symposium was to review recent progress in the study of our Galaxy, to define current problems, and to explore prospects for future development. The Symposium programme would emphasize the large-scale characteristics of our Galaxy, and highlight both the historical development of our understanding of the Milky Way Galaxy and the importance of studies of external galaxies to this understanding. The Symposium was sponsored by four IAU Commissions: 33 (Structure and Dynamics of the Galactic System), 28 (Galaxies), 34 (Interstellar Matter) and 41 (History of Astronomy). The Scientific Organizing Committee, listed on page xviii, represented a broad range of nationalities and of expertise, including two historians of science. A meeting of the Committee, held during the IAU General Assembly at Patras, provided an excellent opportunity to discuss plan and format of the Symposium, topics and speakers; thereafter, the-Committee was regularly consulted by letter and telephone. IAU Symposium 106 was held at Groningen on 30 May - 3 June 1983, in the new building occupied by the Kapteyn Institute since January 1983. There were about 200 participants, coming from as many as 25 countries.

"If simple perfect laws uniquely rule the universe, should not pure thought be capable of uncovering this perfect set of laws without having to lean on the crutches of tediously assembled observations? True, the laws to be discovered may be perfect, but the human brain is not. Left on its own, it is prone to stray, as many past examples sadly prove. In fact, we have missed few chances to err until new data freshly gleaned from nature set us right again for the next steps. Thus pillars rather than crutches are the observations on which we base our theories; and for the theory of stellar evolution these pillars must be there before we can get far on the right track. " These words written by Martin Schwarzschi1d in his famous book en titled "Structure and Evolution of the Stars"(1958) remind us how necessary and fruitful is the interplay of stellar evolution theory and observations. Clearly, observations are the great censor by their possibility of confirming or contradicting theoretical constructions. In addition, they have a driving role: new and sometimes unexpected facts may give rise to progressive ideas and stimulate further theoretical developments. In turn, theory, in its major role of sifting out and placing the facts in a logical sequence based on physical laws, must also be predictive and indicate new and pertinent observations to be undertaken."

I.A.U. symposium No. 110 on VLBI and Compact Radio Sources was held in Bologna, Italy from June 27 to July 1, 1983. 166 participants from 19 countries were registered and 106 invited and contributed papers were registered. The scientific presentations and discussion concentrated on VLBI observation and interpretation of galactic and extragalactic radio sour ces, including topics as diverse as quasars and galactic nuclei, inter stellar masers, pulsars, and astrometry. Geodetic applications and tech nical development were treated only briefly, as these topics have been the subject of other recent international symposia. Since the first VLBI observations in 1967, sensitivity, resolution, and image quality have improved dramatically. Radio maps shown at the symposium were of comparable quality to conventional synthesis maps be ing made at the time of the first VLBI experiments 15 years ago, but with a resolution more than a factor of 1000 better. We wanted to accommodate the large number of contributed papers in this rapidly developing field, but there was inadequate time for normal oral presentations and discussion. We therefore asked that all contrib uted papers be put on display for at least 24 hours prior to a brief oral summary. A question and discussion period followed groups of oral pres entations on the same or similar topic. In this way the opportunity for interactive discussion, not available in conventional poster displays, was preserved."

Proceedings of IAU Symposium No. 108 held in Tubingen, West Germany, September 5-8, 1983

IAU Symposium 101, Supernova Remnants and Their X-ray Emission, was held on the Island of San Giorgio, Venice, 30 August - 2 September 1982. It was co-sponsored by the National Research Council, Italy, the University of Padua, the Observatory of Padua, and the International Astronomical Union, and was hosted by the Cini Foundation. The contents of this volume show the wide range of disciplines that are involved in supernova remnant research. Many new results were presented, not only from the X-ray observations from the Einstein Observatory but also from observations at optical and radio wavelengths. This has led to the stimulation of theoretical work, much of which attempts to accommodate in a more unified way all of these observations. Research on supernova remnants of all ages was reported. Perhaps the most impressive part of all this work is the way in which observations at all wavelengths have extended well outside the Galaxy to other members of the Local Group and beyond. The Symposium was attended by scientists from 15 countries. Twenty five invited papers and sixty-eight shorter contributions were presented during the 4-day meeting. Thirty-three of these shorter contributions were presented in poster sessions. This volume contains almost all (89) of those contributions. They are followed by discussions which took place after each verbal presentation. Since the availability of the discussions was left to the individual contributors, they are not complete, but those contained in this volume convey some idea of the nature of the exchanges."

IAU Symposium 103 was held at University College London, August 9-13 1982. This volume contains the proceedings of the meetin- invited papers, abstracts of contributed papers, and discussion. As is nON custanary with the proceedings of IAU Symposia, the manuscript was canpiled fran camera-ready copy. The Editor was responsible for the preparation of the abstracts of the contributed papers and the discussion, the authors of the invited papers for the preparation of their 0Nn reviews. The discussion at the meeting was lively and infonnative, and the Editor hopes that a reasonably faithful and readable record of the discussion is to be found in these proceedings. In accordance with the wish of the Scientific Organising Committee, an object index has been canpiled and appended. It is to be hoped that the index will augment the usefulness of the volune. The Editor is greatly indebted to M. J. Barlow for his help in preparing the index. Financial assistance for the meeting was provided by the IAU and University College London. The hospitality received during the excursion to the Old Royal Observatory and National Maritime MUseum, Greenwich, is gratefully acknowledged. The task of editing these proceedings has been greatly facilitated by the excellent secretarial assistance of V. A. Kerr. David Flower Durham, October 1982 xiii D. R. Flower (ed.), Planetary Nebulae, xiii.

It was particulary appropriate that the IAU Symposium N 100 be held in Besan~on in 1982 (August 9-13), since this coincided with the 100th anniversary of the Observatoire de Besan~on. The meeting was held on the campus of the Universite de Franche-Comte and was sponsored by IAU commission 28 and co-sponsored by commissions 33 and 40. It was organized under the auspices of the Ministere de l'Education Nationale, the Centre National de la Recherche Scientifique and the Institut National d'Astronomie et de Geophysique. It was attended by 166 scien- tists from 22 countries. The subject of the symposium was internal kinematics and dynamics of galaxies and it was aimed to confront recent theoretical developments in this field with the wealth of new observational mate- rial obtained during the last few years. Barred galaxies and spiral structure were two major topics, though unfortunately at the last minute the main proponent of one of the spiral formation theories was unable to attend. The program included 23 reviews, 53 contributions and 39 poster papers, and there was ample time for discussion.

The Origin and Evolution of Galaxies is the outstanding problem of modern cosmology. Fortunately. we have a firm cosmological framework on which to base our theories (the hot big bang) and recently there has been substantial progress in providing observations which potentially can constrain these theories. The problem of galaxy formation is. as a consequence. one involving many diverse branches of physics and astrophysics. It has been the aim of the school. and this compendium of lectures and seminars. to bring together these diverse aspects at a level enabling research workers to understand what is going on in other corners of the subject and to see how progress in each area impinges on the others. We are grateful to the contributors to this volume for allowing us considerable editorial license with their articles. We have attempted to provide a representative sample of the talks that were given at the school besides the texts of the invited lecturers. It is regrettable that for reasons of space we have had to leave out a number of other contributions.

The formative ideas for this symposium originated in 1978 at the IAU Symposium No. 83 on "Mass Loss and Evolution of O-type Stars" held at Qualicum Beach, Vancouver Island, Canada - WR stars generally figure prominently in O-star meetings and vice versa Following general appro val by the IAU Executive Committee the initial ideas were cemented at a subsequent meeting, IAU Colloquium No. 59 on "The Effects of Mass Loss on Stellar Evolution," held at Miramare, Trieste, Italy in 1980, which was attended by the ma, jority of the present Scientific Organising Committee and at which meeting the outline programme for this symposium was formulated. 1981 was considered an appropriate year in which to hold a meeting on WR stars, since the last IAU Symposium devoted to this stellar class had been held a decade earlier, in Buenos Aires (IAU Sym posium No. 49), and during this intervening period a wealth of new observational material had been obtained for WR stars together with significant advances on the theoretical front. The venue for this sym posium was chosen from the requirement, which can be inferred from the above, that a meeting on 'hot' stars take place in an appropriate, sunny climate and followed upon the excellent suggestion of Dr. C. Firmani to hold the symposium in Mexico."

continues to be extremely rewarding. Experiments on future missions, such as the two 1981 Veneras, Gamma Ray Observatory, and the International Solar Polar Mission, will undoubtedly provide new and unexpected discoveries, but the work of the Leningrad group is likely to remain an important contribution to the field for some time to come. c.E.S.R. KEVIN HURLEY Toulouse, France June 9, 1981 CATALOG OF COSMIC GAMMA-RAY BURSTS FROM THE KONUS EXPERIMENT DATA Parts I and II E. P. MAZETS, S. V. GOLENETSKII, V. N. IL'INSKII, V. N. PANOV, R. L. APTEKAR, YU. A. GUR'YAN, M. P. PROSKURA, 1. A. SOKOLOV, Z. Y A. SOKOLOV A, and T. V. KHARITONOV A A. F. Ioffe Physical-Technical Institute, U.S.S.R. Academy of Sciences, Leningrad, U.S.S.R. and A. V. DYATCHKOV and N. G. KHAVENSON Institute of Cosmic Research, U.S.S.R. Academy of Sciences, Moscow, U.S.S.R. (Received 2 July, 1980) Abstract. Data are presented on the temporal structure, fluxes, energy spectra and coordinates of the sources of gamma-ray bursts detected in the KONUS experiment on Venera 1 I and Venera 12 space probes in the period September 1978 to May 1979. The statistical distributions of gamma bursts in duration, intensity, and peak power, as well as the distribution of the burst sources over the celestial sphere presented are based on the updated KONUS information obtained until February 1980.

Donald D. Clayton's Principles of Stellar Evolution and Nucleosynthesis remains the standard work on the subject, a popular textbook for students in astronomy and astrophysics and a rich sourcebook for researchers. The basic principles of physics as they apply to the origin and evolution of stars and physical processes of the stellar interior are thoroughly and systematically set out. Clayton's new preface, which includes commentary and selected references to the recent literature, reviews the most important research carried out since the book's original publication in 1968.