The organization of this Symposium had its beginnings at the International Astronomical Union General Assembly in Grenoble in 1976. The initial "rounding up" of the Scienti fic Organizing Committee was begun by Drs. Snow and Swings; most of us who became the eventual organizing committee met a few times during the Assembly and formulated the essential outlines of the meeting. Extensive correspondence with all the committee subsequently established the program. The idea was to bring together both observers and theoreticians to discuss the stellar winds and mass loss rates and their effects on evolutions of O-type stars. On the observational side, there are now spectroscopic data from the far UV to the near IR regions concerning the stellar winds. There is also information about the free-free emission in the wind from the IR and radio portions of the spectrum. Fortunately, these different detection methods give more or less the same mass loss rate for the one star, s Pup" which has been observed at all wavelengths. One of the intents of the first three sessions of this Symposium is to outline the eXisting data on mass loss rates as it per tains to the O-type stars."

IAU Symposium No. 80, The HR Diagram - The 100th Anniversary of Henry Norris Russell was held on November 2-5, 1977 at the National Academy of Sciences in Washington D. C. , in order to commemmorate the birth of Henry Norris Russell on October 25, 1877 and to review current problems in the use of the Hertzsprung-Russell diagram. The IAU has sponsored two previous conferences concerned mainly with the HR diagram; The Position of Variable Stars in the Hertzsprung-Russell Diagram, a colloquium held at Bamberg in 1965 and The Hertzsprung Russell Diagram (IAU Symposium No. 10, J. L. Greenstein, ed. ) held in Moscow in 1959. In 1974 a conference, Multicolor Photometry and the Theoretical HR Diagram (Dudley Obs. Report No. 9, A. G. D. Philip and D. S. Hayes, eds. ) was held in Albany, N. Y. ; and in 1964 a conference, Basic Data Pertaining to the Hertzsprung-Russell Diagram, was held at the Flagstaff Station of the U. S. Naval Observatory in honor of Ejnar Hertzsprung and to dedicate the 61-inch astrometric reflector. (Vistas in Astronomy Vol. ~, A. Beer and K. Aa. Strand, eds. , Pergamon Press, Oxford). Volume 12 of Vistas in Astronomy, The Henry Norris Russell Memorial Volume (1970), contains a review paper on Changing Interpretations of the Hertzsprung-Russell Diagram 1910-1940, A Historical Note by B. W. Sitterly.

Proceedings of IAU Symposium No. 76 held at Cornell University, Ithaca NY, USA, 6-10 June 1977

Proceedings of IAU Symposium No. 75 held in Geneva, Switzerland, September 6-10, 1976. Dedicated to Solomon Pikel'ner

Symposium No. 73 of the International Astronomical Union was devoted to the obser vational and theoretical aspects of close binary stars. Just over 100 participants attended. The Local Organizing Committee would like to thank the following: IAU for travel grants. IBM United Kingdom Ltd for very generous support in the form of travel grants. The Royal Society for the provision of travel grants to participants from Eastern Europe. We also thank the Director of the Institute of Astronomy, and our colleagues and research students for their moral support and assistance. Finally we thank Pauline Haughey for assisting with the editorial work. PETER EGGLETON SIMON MITTON JOHN WHELAN SCIENTIFIC ORGANIZING COMMITTEE M. Plavec (Chairman), T. Herczeg, E. P. J. van den Heuvel, J. B. Hutchings, G. Larsson-Leander, L. B. Lucy, L. Mestel, B. Paczynski, J. Sahade, B. Warner, R. E. Wilson. LOCAL ORGANIZING COMMITTEE J. A. J. Whelan (Chairman), P. P. Eggleton, S. A. Mitton LIST OF PARTICIPANTS Baldwin, B. W., Victoria, Canada Icke, V., Cambridge, England Bateson, F. M., Tauranga, New Zealand Koumsiachvilli, M., Moscow, U.S.S.R Bath, G. T., Oxford, England Krzeminski, W. A., Warsaw, Poland Batten, A. H., Victoria, Canada Larsson-Leander, G., Lund, Sweden Berthier, E. J., Paris, France Leung, K.-C., Nebraska, U.S.A."

The International Astronomical Union Symposium No. 70 on Be and Shell Stars, the Merrill-McLaughlin Memorial Symposium, was held in Bass River (Cap Cod), Massachusetts, U. S. A. , from September 15th through 18th, 1975. Fifty-three astronomers from Argentina, Belgium, Canada, Czechoslovakia, France, Israel, the United Kingdom, the United States, and the Vatican attended and participated in the Symposium. This volume, which parallels the actual program closely, contains the papers presented at the Symposium plus most of the discussion following the papers. New observational techniques and fresh theoretical ideas have resulted over the past few years in a renewed interest in Be and shell stars. At IAU Symposium No. 51 on Extended Atmospheres and Circumstellar Matter in Spectroscopic Binary Sys tems, the Otto Struve Memorial Symposium, in Parksville, British Columbia, Canada, three years ago, a number of participants expressed the wish to organize a symposium on Be and shell stars. If we wish to identify an official 'Father of IAU Symposium No. 70', it would be Mirek Plavec who, in his capacity as President of IAU Commission 42 (Photometric Double Stars) requested and received the cooperation of Commissions 29 (Stellar Spectra) and 36 (Stellar Atmospheres), suggested an Organizing Committee, and wrote to the IAU General Secretary in 1973 requesting that the IAU Executive Committee approve the proposed confer ence as an IAU Symposium.

The general discussions of the roles of photometric and spectroscopic classification at Cordoba in 1971 (lAU Symposium No. 50), and of the calibration of classification indices at Geneva in 1972 (IAU Symposium No. 54), revealed clearly the steadily in creasing importance of abundance parameters. The multipliCity of these, however, raised so many new problems that it was logical that the 1975 meeting at Lausanne should be concerned with ways in which differences in abundance affect both spectral types and photometric indices. Commissions 29 and 36 joined with Commission 45 in sponsoring this Symposium. Since the date of the meeting came shortly after the formal retirement of Professor William W. Morgan from the University of Chicago, it was quickly agreed that this meeting should be dedicated to him in recognition of his unique contributions to spectral classification. In the opening paper of the Symposium Dr. Bengt Stromgren has summarized these. To his remarks we should add only that it was about 1940 that Morgan first distinguished the group of G- and K-type stars with weak CN bands and metallic lines - stars which have since been recognized as having the abundance of all metals relative to hydrogen much lower than in stars of the solar population. Spectra of two of these, HD 81192 (Boss 2527) and 8 Lep, were later shown as examples of the group in the Yerkes Atlas of 1943."

This textbook gives a clear account of the manner in which knowledge in many branches of physics, such as gravitation, thermodynamics, atomic physics, and nuclear physics, can be combined to gain an understanding of the structure and evolution of stars. A major aim is to present the subject as one in which advances are still being made. The first half is an account of the observational properties of stars and a discussion of the equations that govern their structure. The second part discusses recent theoretical work on stellar evolution. The successes of the theory are stressed, but attention is also drawn to phenomena that are not completely understood. This is a new edition of a widely-used textbook first published in 1970. New topics include mass loss from stars and close binary stars.

The idea of holding this Symposium has its origin in a conversation with G. Con to poulos during the winter of 1973. It was then clear that the progress realized in Stellar Dynamics since the Thessaloniki symposium had given a new shape to the field. Other meetings such as the C. N. R. S. colloquium held in Paris in 1967 or the LA. V. colloquium held in Cambridge, England, in 1970 had in the meantime given opportunities to review the advances achieved in several branches of this field. We thought that time had come to organize a general confrontation of the new results obtained in the approach of the gravitational N-body problem by different methods, in the investigation of spherical and flattened systems, in the comparisons with ob servations and in more theoretical speculations on orbits, integrals of motion, dense nuclei or relativistic stellar dynamics. Things were made easy by the support of Commissions 33 and 37 which welcomed the proposition and by 1. R. King who accepted to act as Chairman of the Scientific Organizing Committee. The final decision to meet in Besan'Yon was taken during the XVth General Assembly of the LA. U. in Sydney in August 1973. The members of the Organizing Committee were: 1. R. King (Chairman), G. Con topoulos, A. Hayli, M. Henon, G. Hori, D. Lynden-Bell, L. Perek, L. Spitzer, R. Wielen, Ya. Zel'dovich while the members of the Local Committee were: A."

This book contains a set of articles based on a session of the annual meeting of the American Association for the Advancement of Science held in San Francisco in February, 1974. The reason for the meeting arose from the need to communicate to the largest possible scientific community the dramatic advances which have been made in recent years in the understanding of collapsed objects: neutron stars and black holes. Thanks to an unprecedented resonance between X-ray, y-ray, radio and optical astronomy and important new theoretical developments in relativistic astro physics, a new deep understanding has been acquired of the physical processes oc curring in the late stages of evolution of stars. This knowledge may be one of the greatest conquests of man's understanding of nature in this century. This book aims to give an essential and up-to-date view in this field. The analysis of the physics and astrophysics of neutron stars and black holes is here attacked from both theoretical and experimental points of view. In the experimental field we range from the reviews and catalogues of galactic X-ray sources (R. Gursky and E. Schreier) and pulsars (E. Groth) to the observations of the optical counter part of X-ray sources (P. Boynton) to finally the recently discovered gamma-ray bursts (I. Strong) and pulse astronomy R. B. Partridge)."

Colloquia and symposia have almost become a tradition among the variable-star astronomers; those held more or less regularly at Bamberg and Budapest have become well known. For a change, this time the organizing committee of Commission 27 decided to hold an LA. U. symposium in Moscow and to adopt as a special topic the relation between variable stars and the evolution of stars and stellar systems. This symposium, No. 67 in the LA. U. series, was prepared by two committees, a by B. V. Kukarkin, and a local one with V. A. Ambartsumian scientific one chaired as chairman, and G. S. Khromov as executive secretary. It was held in Moscow at the Physical and Astronomical Institutes of the Lomonosov University from July 29 to August 4, 1974. The symposium was opened with three short welcoming speeches by V. A. Ambartsu mian, J. M. Ternov (vice-rector of Moscow University), and B. V. Kukarkin. All three stressed the importance of the study of variable stars in connection with the evolution of stars and stellar systems, the role of the Russian astronomers in these studies, and the necessity of international cooperation."

The XXth meeting of the IAU in Australia in 1973 made the venue for the IAU Symposium No. 59 on Stellar Instability and Evolution, at Mount Stromlo Obser vatory on August 16-18, a very appropriate one. Many of the current and former staff of Mount Stromlo Observatory (operated by the Australian National Univer sity) have specialized in the study of variable stars and it was with considerable pleasure that Mount Stromlo Observatory accepted the responsibility of hosting and making the local arrangements for IAU Symposium No. 59. The Scientific Organizing Committee was particularly active in formulating the program and comprised Drs N. Baker, P. Demarque, M. Feast, G. Herbig, I. Iben, P. Ledoux, J. Ostriker and E. Schatzman. The aim of the Committee was to integrate the review and contributed papers on the particular instability mechanisms involved, their observational manifestations and their relation to the internal structure of the star as inferred from its evolutionary history. The Local Organizing Committee consisted of Miss P. Petrie and A. W. Rodgers."

'Galactic Radio Astronomy' was chosen as the subject of this Symposium, which was held in conjunction with the IAU General Assembly that took place in Sydney in August 1973, largely because it is a very suitable Southern Hemisphere topic. This results in part from the advantages of a southern location in studying the Galaxy and in part from the long association of Australia with radio astronomy. Following the General Assembly, the Symposium was held at the Surf air Inter national Hotel in Maroochydore, Queensland, from 3 to 7 September, 1973. The conference participants were effectively isolated from the rest of the world during the Symposium, and the excellent spring weather and geographical situation led to the development of an unusually good rapport. The Symposium was sponsored by Commissions 40, 33, and 34. The Organizing Committee was composed of A. H. Barrett (chairman), J. E. Baldwin, D. S. Heeschen, F. J. Kerr, J. Lequeux, S. W. McCuskey, P. G. Mezger, B. Y. Mills, Yu. N. Parijskij, B. J. Robinson, H. van der Laan, and H. F. Weaver. The Local Committee, consisting ofB. J. Robinson, N. G. Seddon, and P. J. Kelly, looked after the arrangements in very fine style. The Symposium was supported financially by the IAU, the Australian Academy o Science, the CSIRO Division of Radiophysics, Union Carbide Australia Limited, and the Science Foundation for Physics within the University of Sydney."

Proceedings of IAU Symposium No. 58 held in Canberra, Australia, August 12-15, 1973

Proceedings of IAU Symposium No. 53 held in Boulder, Colorado, 21-26 August 1972

In connection with arranging IAU Symposium No. 50 on 'Spectral Classification and Multicolour Photometry', sponsored by Commissions 45 and 25, it was decided to exclude all calibration problems. Instead it was agreed that we should attempt to arrange a separate symposium, dealing with the fundamental problems of the cali bration of absolute magnitudes and temperatures of stars. The Executive Committee of the IAU accepted our proposal, and IAU Symposium No. 54 was held in Geneva on September 12-15, 1972, sponsored by thefollowing IAU Commissions: 24, 25, 29, 33, 35, 37,44 and 45. It was attended by about 90 scientists representing 16 countries. The Symposium was divided into eight sessions. Each session started with a review paper by an invited speaker; this was followed by a general discussion including a few contributed papers. The contents of the present volume follow closely the programmes of the individual sessions of the Symposium. Most of the recorded discussions have been kept, and only in a few cases have the order of questions and comments been altered so as to obtain more homogeneity in the presentation."

The proposal to organize a Symposium on circumstellar matter and extended atmo spheres in binary systems was first made by the Dominion Astrophysical Observatory to the Executive Committee of the International Astronomical Union in the summer of 1969. It received the support of the presidents of Commissions 29 (Stellar Spectra), 30 (Radial Velocities), 36 (Stellar Atmospheres), and 42 (Photometric Double Stars). Approval in principle was given by the Executive Committee almost immediately, and the Committee further suggested that the Symposium be officially designated the Struve Memorial Symposium. Final approval was given at the time of the 1970 General Assembly of the Union. when the dates of the Symposium were set for August or September, 1972. The Organizing Committee set up consisted of K. O. Wright (Chairman), A. H. Batten, K. -H. B6hm, A. A. Boyarchuk, G. Larsson-Leander, and M. Plavec. In addition, J. Sahade and F. B. Wood acted as advisory members. Local organization was entrusted to a committee consisting of A. H. Batten, E. K. Lee, and C. D. Scarfe. The final dates selected were September 6-12, 1972, and the Sym posium was held at the Island Hall Hotel, Parksville, B. C., on Vancouver Island some 90 miles from Victoria. The Organizing Committee attempted to arrange a Symposium of the type in which no contributed papers would be presented and discussion would range as widely as possible over the field covered by the six invited review papers."

We have in this volume, compiled a connected account of the proceedings of the Symposium on Wolf-Rayet and High-Temperature Stars held at Buenos Aires. The Organizing Committee had assigned broad areas of topical interest to be reviewed by invited speakers. Each of these presentations was followed by lengthy discussions that were tape recorded and transcribed later. These discussions have been edited only to a limited extent. We have shortened them and rearranged them to bring about a greater coherence. We have, however, attempted to retain the tenor of the discussions, the flavour of impromptu remarks and the continuity of an argument. Much of the success of such a venture depends on the contributors to the discussions. To be able to make these thoughts available to a larger audience has been the task of those re sponsible for the elaborate tape recording of the proceedings. We thank those at the Instituto de Astronomia y Fisica del Espacio for the efficient way in which this re sponsibility has been discharged. Many at Buenos Aires and Kodaikanal have contrib uted efficient assistance to the preparation of this volume and we are deeply indebted for their help. In particular, two amongst these, Nora Martinez and A. M. Batcha have contributed overwhelmingly both to the organization of the symposium and the final preparation of the symposium volume. Financial support for this symposium came from the International Astronomical Union and the Argentine National Research Council."

This extensively illustrated book presents the astrophysics of galaxies since their beginnings in the early Universe. It has been thoroughly revised to take into account the most recent observational data, and recent discoveries such as dark energy. There are new sections on galaxy clusters, gamma ray bursts and supermassive black holes. The authors explore the basic properties of stars and the Milky Way before working out towards nearby galaxies and the distant Universe. They discuss the structures of galaxies and how galaxies have developed, and relate this to the evolution of the Universe. The book also examines ways of observing galaxies across the whole electromagnetic spectrum, and explores dark matter and its gravitational pull on matter and light. This book is self-contained and includes several homework problems with hints. It is ideal for advanced undergraduate students in astronomy and astrophysics.

Richly illustrated with a luminous and informative collection of maps, photographs, and graphics, this atlas is the perfect companion for exploring the wonders of the universe as viewed from Earth. This expansive illustrated atlas invites readers to roam the night sky for constellations, planets and moons, eclipses, comets and meteor showers, auroras, and deep-sky treasures including nebulae and galaxies-many visible to the naked eye and all with binoculars or a backyard telescope. Beginning with basic space science and including a complete set of night sky maps for all four seasons in the Northern and Southern Hemispheres, this fascinating book guides the reader toward the most rewarding observations. A unique chapter on astro-tourism highlights ancient observatories, dark-sky preserves, and other global destinations for the sky-seeking traveller; a final chapter details current and future space missions and what they might discover. Richly illustrated with awe-inspiring imagery-including photos from space missions and telescopes, science-based artists' interpretations, and explanatory graphics-the book also contains 170 maps and charts of planets, moons, and constellations, from Earth's moon to moons of Saturn. Practical advice throughout helps readers see what they have been reading about, building key observational skills such as "star hopping" from easy-to-find stars to fainter deep-sky objects and focusing on "deep sky treasures:" areas rich in observable phenomena. Approachable and authoritative, gorgeous and fascinating, this large-format illustrated atlas will intrigue all who love to gaze up in wonder at the night sky-and find themselves wanting to know more.

Celebrating the centenary of George Ellery Hale's discovery of magnetic fields in sunspots, IAU Symposium 273 reviews the recent advances made in the fields of solar and stellar magnetism. Sunspots are responsible for the time-varying properties of the Sun, including the solar irradiance. Combined study of the spots on the Sun and on other stars provides a greater understanding of sunspot formation and behaviour on a long-term basis. On the other hand, stellar observations can be best understood by using detailed properties of the Sun as a reference point. This volume contains reviews and research articles from solar and stellar astronomers on the recent findings of solar and stellar magnetism using observational, theoretical and simulation studies of the Sun and the stars to approach the subject in a unified manner. Its findings are useful to advanced students and researchers in solar and stellar astronomy.

SHORTLISTED FOR THE ROYAL SOCIETY SCIENCE BOOK PRIZE 2021 FINALIST FOR THE PEN/E.O. WILSON LITERARY SCIENCE WRITING AWARD AN AMAZON BEST BOOK OF 2020 To be an astronomer is to journey to some of the most inaccessible parts of the globe, braving mountain passes, sub-zero temperatures, and hostile flora and fauna. Not to mention the stress of handling equipment worth millions. It is a life of unique delights and absurdities ... and one that may be drawing to a close. Since Galileo first pointed his telescope at the heavens, astronomy has stood as a fount of human creativity and discovery, but soon it will be the robots gazing at the sky while we are left to sift through the data. In The Last Stargazers, Emily Levesque reveals the hidden world of the professional astronomer. She celebrates an era of ingenuity and curiosity, and asks us to think twice before we cast aside our sense of wonder at the universe.

Based on the very popular liberal arts course Bob Bless has taught at University of Wisconsin for many years, this book provides a rich, historical approach to introductory astronomy. It is ideal for use in an introductory astronomy course for nonmajors. In the fifteen years since the first edition of this text was published, several new concepts such as dark matter, dark energy, and an incredible expansion of the universe (inflation) have been developed. Furthermore, many of the exotic effects predicted by General Relativity (e.g. black holes, warped space) have gone from being interesting theoretical speculations to useful practical tools for understanding the universe. This book aims to give an overview of astronomy, but in such a way that the non-science major can get a feeling for how science actually developed with its false starts and wrong turns, which observational evidence eventually corrected, and also to describe the incredible recent developments in our understanding of the physical universe. Several chapters of this 2nd edition have been extensively revised to include these recent developments. Because it has become increasingly difficult to "cover" all of astronomy in a one-semester course, this edition has largely omitted coverage of the physical nature of the objects in our, and other, planetary systems, although a discussion of the possibility of life elsewhere closes the book.

Illustrated with breathtaking images of the Solar System and of the Universe around it, this book explores how the discoveries within the Solar System and of exoplanets far beyond it come together to help us understand the habitability of Earth, and how these findings guide the search for exoplanets that could support life. The author highlights how, within two decades of the discovery of the first planets outside the Solar System in the 1990s, scientists concluded that planets are so common that most stars are orbited by them. The lives of exoplanets and their stars, as of our Solar System and its Sun, are inextricably interwoven. Stars are the seeds around which planets form, and they provide light and warmth for as long as they shine. At the end of their lives, stars expel massive amounts of newly forged elements into deep space, and that ejected material is incorporated into subsequent generations of planets. How do we learn about these distant worlds? What does the exploration of other planets tell us about Earth? Can we find out what the distant future may have in store for us? What do we know about exoworlds and starbirth, and where do migrating hot Jupiters, polluted white dwarfs, and free-roaming nomad planets fit in? And what does all that have to do with the habitability of Earth, the possibility of finding extraterrestrial life, and the operation of the globe-spanning network of the sciences?