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."

'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."

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."

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

"An Introduction to Stellar Astrophysics" aspires to provide the reader with an intermediate knowledge on stars whilst focusing mostly on the explanation of the functioning of stars by using basic physical concepts and observational results.

The book is divided into seven chapters, featuring both core and optional content: Basic conceptsStellar FormationRadiative Transfer in StarsStellar AtmospheresStellar InteriorsNucleosynthesis and Stellar Evolution andChemically Peculiar Stars and Diffusion.

Student-friendly features include: Detailed examples to help the reader better grasp the most important conceptsA list of exercises is given at the end of each chapter and answers to a selection of these are presented.Brief recalls of the most important physical concepts needed to properly understand stars.A summary for each chapterOptional and advanced sections are included which may be skipped without interfering with the flow of the core content.

This book is designed to cover the most important aspects of stellar astrophysics inside a one semester (or half-year) course and as such is relevant for advanced undergraduate students following a first course on stellar astrophysics, in physics or astronomy programs. It will also serve as a basic reference for a full-year course as well as for researchers working in related fields.

Featuring detailed commented spectral profiles of more than one hundred astronomical objects, in colour, this spectral guide documents most of the important and spectroscopically observable objects accessible using typical amateur equipment. It allows you to read and interpret the recorded spectra of the main stellar classes, as well as most of the steps from protostars through to the final stages of stellar evolution as planetary nebulae, white dwarfs or the different types of supernovae. It also presents integrated spectra of stellar clusters, galaxies and quasars, and the reference spectra of some terrestrial light sources, for calibration purposes. Whether used as the principal reference for comparing with your recorded spectra or for inspiring independent observing projects, this atlas provides a breathtaking view into our Universe's past. The atlas is accompanied and supplemented by Spectroscopy for Amateur Astronomers, which explains in detail the methods for recording, processing, analysing and interpreting your spectra.

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.

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?

The classic account of the structure and evolution of the early universe from Nobel Prize-winning physicist P. J. E. Peebles An instant landmark on its publication, The Large-Scale Structure of the Universe remains the essential introduction to this vital area of research. Written by one of the world's most esteemed theoretical cosmologists, it provides an invaluable historical introduction to the subject, and an enduring overview of key methods, statistical measures, and techniques for dealing with cosmic evolution. With characteristic clarity and insight, P. J. E. Peebles focuses on the largest known structures-galaxy clusters-weighing the empirical evidence of the nature of clustering and the theories of how it evolves in an expanding universe. A must-have reference for students and researchers alike, this edition of The Large-Scale Structure of the Universe introduces a new generation of readers to a classic text in modern cosmology.

A pocket-style edition based on the New York Times bestseller A Brief Welcome to the Universe offers a breathtaking tour of the cosmos, from planets, stars, and galaxies to black holes and time loops. Bestselling authors and acclaimed astrophysicists Neil deGrasse Tyson, Michael A. Strauss, and J. Richard Gott take readers on an unforgettable journey of exploration to reveal how our universe actually works. Propelling you from our home solar system to the outermost frontiers of space, this book builds your cosmic insight and perspective through a marvelously entertaining narrative. How do stars live and die? What are the prospects of intelligent life elsewhere in the universe? How did the universe begin? Why is it expanding and accelerating? Is our universe alone or part of an infinite multiverse? Exploring these and many other questions, this pocket-friendly book is your passport into the wonders of our evolving cosmos.

'fascinating' Brian Cox This is the story of citizen science. Where once astronomers sat at the controls of giant telescopes in remote locations, praying for clear skies, now they have no need to budge from their desks, as data arrives in their inbox. And what they receive is overwhelming; projects now being built provide more data in a few nights than in the whole of humanity's history of observing the Universe. It's not just astronomy either-dealing with this deluge of data is the major challenge for scientists at CERN, and for biologists who use automated cameras to spy on animals in their natural habitats. Artificial intelligence is one part of the solution-but will it spell the end of human involvement in scientific discovery? No, argues Chris Lintott. We humans still have unique capabilities to bring to bear-our curiosity, our capacity for wonder, and, most importantly, our capacity for surprise. It seems that humans and computers working together do better than computers can on their own. But with so much scientific data, you need a lot of scientists-a crowd, in fact. Lintott found such a crowd in the Zooniverse, the web-based project that allows hundreds of thousands of enthusiastic volunteers to contribute to science. In this book, Lintott describes the exciting discoveries that people all over the world have made, from galaxies to pulsars, exoplanets to moons, and from penguin behaviour to old ship's logs. This approach builds on a long history of so-called 'citizen science', given new power by fast internet and distributed data. Discovery is no longer the remit only of scientists in specialist labs or academics in ivory towers. It's something we can all take part in. As Lintott shows, it's a wonderful way to engage with science, yielding new insights daily. You, too, can help explore the Universe in your lunch hour.

The idea of the symposium came during the XVllth General Assembly of the IAU at Montreal. The Working Group on Be stars adopted both the proposal of holding a meeting, and of having it at the Universitats- sternwarte Munich. The meeting was organized under the auspices of IAU Comm. 29 (Stel- lar Spectra) and the sponsorship of Comm. 45 (Stellar Classification). The Scientific Organizing Committee was composed of Mercedes Jaschek (chairman), W. Bonsack, C. de Loore, A. Feinstein, H. G. Groth, P. Harmanec, L. Houziaux, A. M. Hubert-De1p1ace, L. S. Luud, A. Slettebak and A. Underhill. The members of this committee are to be thanked for their devotion to the organization of what turned out to be a very successful meeting. The program was organized on an observational approach, comprising sessions on photometry, polarization, spectroscopy, infrared observations, rotation and binarity, X-ray observations, UV observations and mass loss, and atmospheric models. Each session started with an invited summary paper, followed by a number of contributions. The different sessions were chaired by A. Feinstein, R. Sta1io, C. de Loore, Ch. Fehrenbach, J. P. Swings, C. Jaschek, A. Sapar, G. T. Traving, M. de Groot and H. G. Groth. Upon request of the Working Group., a special session was devoted to bibliographic problems and observing campaigns. The Dean of the Faculty for Physics 0.GBP the Ludwig-Maximilians-, Universitat welcomed the participants at the beginning of the Symposium. The meeting was closed by a summary talk, delivered by ~. P. Snow.

Written in an informal and engaging style, this volume traces the discoveries that led to our understanding of the size and structure of the Milky Way, and the conclusive evidence for a massive black hole at its center. Robert H. Sanders, an astronomer who witnessed many of these developments, describes how we parted the veil of interstellar dust to probe the strange phenomena within. We now know that the most luminous objects in the Universe - quasars and radio galaxies - are powered by massive black holes at their hearts. But how did black holes emerge from being a mathematical peculiarity, a theoretical consequence of Einstein's theory of gravity, to become part of the modern paradigm that explains active galactic nuclei and galaxy evolution in normal galaxies such as the Milky Way? This story, aimed at non-specialist readers and students and historians of astronomy, will both inform and entertain.

Discover the mysteries of the Universe and journey to galaxies beyond our own in this fact-packed companion to space. From icy worlds and hot, fiery giants to the biggest telescopes and latest spacecraft, this book covers more than 40 profiles of the planets, stars, and objects in our universe. Find out all about our neighboring planets, from tiny Mercury to gigantic Jupiter. Discover what lies beyond our solar system and the stars we can see in the night sky. Learn about the latest space technology and when humans may finally land on Mars. Broken down by type, each object is presented in a clear, engaging way, with stunning images and bite-sized chunks of information. Detailed NASA photography brings the mysteries of outer space to life, while pronunciation guides help with tricky names, and a visual index gives a quick overview of all the key objects in the book. Filled with fascinating details for every young stargazer and budding astronaut, My Book of Stars and Planets is the perfect first reference book on space and the universe for kids.

Ongoing studies in mathematical depth, and inferences from helioseismological' observations of the internal solar rotation have shown up the limitations in our knowledge of the solar interior and of our understanding of the solar dynamo, manifested in particular by the sunspot cycle, the Maunder minimum, and solar flares. This second edition retains the identical overall structure as the first edition, but is designed so as to be self-contained with the early chapters presenting the basic physics and mathematics underlying cosmical magnetohydrodynamics, followed by studies of the specific applications appropriate for a book devoted to a central area in astrophysics.
New to this edition:
Chapter 6 gives an account of the present state of dynamo theory in general, and Chapter 8 the applications to the Sun and to other Late-Type' stars with differing rotation rates -- the Solar-Stellar Connection'. The minority of the more massive Early-Type' stars that are observably magnetic are well described by theoblique rotator' model, with a quasi-steady, fossil' magnetic structure frozen' into the highly conducting, non-turbulent envelope. Chapter 9 deals with the considerable progress on the associated theoretical problems.
Chapter 7 contains new material, relevant to both Late- and Early-Type Main Sequence stars, to the evolved Red Giants, and also to contracting pre-Main Sequence stars (Chapter 10}, which show the highest degree of magnetic activity (the magneto-rotational instability, and the magneto-centrifugal winds emitted by the surrounding accretion disk'). In the earlier phases of star formation in molecular clouds (Chapters 11-12), magneto-turbulence' is emerging as the appropriate scenario for the prediction of the mass spectrum of proto-stars, and the associated formation of planetary satellites. Chapter 14 describes developments in the study of the magnetosphere of a pulsar' -- a magnetized neutron star -- consisting of spontaneously generated electron-positron pairs.

Massive stars play a crucial role in the Universe: they are important drivers for the photometric and chemical evolution of galaxies; they are sources of important elements, including those necessary for life; and, with their strong winds and supernova explosions, they feed the interstellar medium with momentum and kinetic energy, impacting on the star formation rate. Knowledge of the evolution of massive stars is important not only for stellar physics, but also for probing the evolution of galaxies and their star formation histories throughout cosmic time. This volume provides an introduction to these topics and to the techniques used to investigate the properties of massive stars, including asteroseismology, spectropolarimetry, and interferometry. It highlights synergies between these new techniques and more classical methods, to create a synthetic view of massive stars, leading researchers towards new and innovative solutions to the most topical questions regarding the evolution of massive stars.

Evolution of Stars and Stellar Populations is a comprehensive presentation of the theory of stellar evolution and its application to the study of stellar populations in galaxies. Taking a unique approach to the subject, this self-contained text introduces first the theory of stellar evolution in a clear and accessible manner, with particular emphasis placed on explaining the evolution with time of observable stellar properties, such as luminosities and surface chemical abundances. This is followed by a detailed presentation and discussion of a broad range of related techniques, that are widely applied by researchers in the field to investigate the formation and evolution of galaxies.
This book will be invaluable for undergraduates and graduate students in astronomy and astrophysics, and will also be of interest to researchers working in the field of Galactic, extragalactic astronomy and cosmology.
* comprehensive presentation of stellar evolution theory
* introduces the concept of stellar population and describes "stellar population synthesis" methods to study ages and star formation histories of star clusters and galaxies.
* presents stellar evolution as a tool for investigating the evolution of galaxies and of the universe in general.

Stellar magnetism is the study of the magnetic field of the Sun and other stars and is a rapidly developing field of astrophysics. This book, an authoritative account with broad astronomical scope, has grown out of the lifelong work of an outstanding researcher in the subject.

This text, written by two leading experts, reviews the historical observations of supernova explosions in our Galaxy over the past two thousand years and discusses modern observations of the remnants of these explosions at radio and other wavelengths.

This text describes the microscopic physics operating in stars and demonstrates how stars respond from formation, through hydrogen-burning phases, up to the onset of helium burning. Intended for beginning graduate students and senior undergraduates with a solid background in physics, it illustrates the intricate interplay between the microscopic physical processes and the stars' macroscopic responses. The volume starts with the gravitationally contracting phase which carries the star from formation to the core hydrogen-burning main sequence, through the main sequence phase, through shell hydrogen-burning phases as a red giant, up to the onset of core helium burning. Particular emphasis is placed on describing the gravothermal responses of stars to nuclear transformations in the interior and energy loss from the surface, responses which express the very essence of stellar evolution. The volume is replete with many illustrations and detailed numerical solutions to prepare the reader to program and calculate evolutionary models.

In the interstellar medium - the space between the stars in galaxies - new stars are born from material that is replenished by the debris ejected by stars when they die. This book is a comprehensive manual for studying the collisional and radiative processes observed in the interstellar medium. This second edition has been thoroughly updated and extended to cover related topics in radiation theory. It considers the chemistry of the interstellar medium both at the present epoch and in the early Universe, and discusses the physics and chemistry of shock waves. The methods of calculation of the rates of collisional excitation of interstellar molecules and atoms are explained, emphasising the quantum mechanical method. This book will be ideal for researchers involved in the interstellar medium and star formation, and physical chemists specialising in collision theory or in the measurement of the rates of collision processes.

This 2007 volume presents the lectures from the sixteenth Winter School of the Instituto de Astrofisica de Canarias, which was dedicated to extrasolar planets. Research into extrasolar planets is one of the most exciting fields of astrophysics, and the past decade has seen a research leap from speculations on the existence of planets orbiting other stars to the discovery of around 200 planets to date. The book covers a wide range of issues, from the state-of-the-art observational techniques used to detect extrasolar planets, to the characterizations of these planets, and the techniques used in the remote detection of life. It also looks at the insights we can gain from our own Solar System, and how we can apply them. The contributors, all of high-standing in the field, provide a balanced and varied introduction to extrasolar planets for research astronomers and graduate students, bridging theoretical developments and observational advances.

IAU Symposium 272 presents an overview of the latest research into active OB stars. These massive, volatile objects serve as test beds for extreme conditions, and research into them has entered a new era with the advent of new space and round-based instrumentation. In this volume, renowned experts discuss the cutting-edge observations, state-of-the-art modeling and recently developed techniques such as asteroseismology, interferometry and spectropolarimetry that have improved our understanding of these extreme objects. Asteroseismology allows us to infer the internal structure of massive stars and their rotation; high-resolution spectropolarimetry provides clues about magnetic fields and the confinement of their circumstellar environments; and interferometry probes the shape of these environments and investigates differential rotation. Written for researchers and graduate students, this volume will appeal to all those interested in extreme physical processes as tools to study structure evolution and mass loss of active OB stars.

Founded in 1911, the AAVSO boasts over 1200 members and observers and is the world's largest non-profit organization dedicated to variable star observation. This timely book marks the AAVSO's centennial year, presenting an authoritative and accurate history of this important association. Writing in an engaging and accessible style, the authors move chronologically through five eras of the AAVSO, discussing the evolution of its structure and purpose. Throughout the text, the main focus is on the thousands of individuals whose contributions have made the AAVSO's progress possible. Describing a century of interaction between amateur and professional astronomers, the authors celebrate the collaborative relationships that have existed over the years. As the definitive history of the first hundred years of the AAVSO, this text has broad appeal and will be of interest to amateur and professional astronomers, as well as historians and sociologists of science in general.