Studies on the populations of luminous stars in nearby resolved galaxies have revealed a complex distribution in the luminosity–temperature plane (the HR diagram). The fundamentals of massive star evolution are mostly understood, but the roles of mass loss, episodic mass loss, rotation, and binarity are still in question. Moreover, the final stages of these stars of different masses and their possible relation to each other are not understood. The purpose of this volume is to provide a current review of the different populations of evolved massive stars. The emphasis is on massive stars in the Local Group, the Magellanic Clouds, and the nearby spirals M31 and M33.

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

A review of the new subject of extragalactic stellar astrophysics - for both graduate students and researchers working in astrophysics.

Our knowledge of the molecular gas content in galaxies has advanced rapidly in the past decade with systematic surveys from ground-based radio facilities, coupled with advances in observations and modeling of the thermal dust emission associated with the gas. This Symposium Proceedings provides a timely overview of the latest observations of molecular gas and dust in the Milky Way and in other galaxies. It also covers related topics including the initial conditions for star formation, observational tracers of star formation and interstellar conditions, and simulations of the turbulent, multiphase interstellar medium. Featuring ten review articles by leaders in the field, and including early results and prospects for the ALMA observatory, this volume will prove especially useful for graduate students or scientists who are pursuing or planning research in this area.

In 1965 Fritz Zwicky proposed a class of supernovae that he called "Type V", described as "excessively faint at maximum". There were only two members, SN1961v and Eta Carinae. We now know that Eta Carinae was not a true supernova, but if it were observed today in a distant galaxy we would call it a "supernova impostor". 170 years ago it experienced a "great eruption" lasting 20 years, expelling 10 solar masses or more, and survived. Eta Carinae is now acknowledged as the most massive, most luminous star in our region of the Galaxy, and it may be our only example of a very massive star in a pre-supernova state. In this book the editors and contributing authors review its remarkable history, physical state of the star and its ejecta, and its continuing instability. Chapters also include its relation to other massive, unstable stars, the massive star progenitors of supernovae, and the "first" stars in the Universe.

Astronomy and Astrophysics Abstracts, which has appeared in semi-annual volumes since 1969, is de voted to the recording, summarizing and indexing of astronomical publications throughout the world. It is prepared under the auspices of the International Astronomical Union (according to a resolution adopted at the 14th General Assembly in 1970). Astronomy and Astrophysics Abstracts aims to present a comprehensive documentation of literature in all fields of astronomy and astrophysics. Every effort will be made to ensure that the average time interval between the date of receipt of the original literature and publication of the abstracts will not exceed eight months: This time interval is near to that achieved by monthly abstracting journals, com pared to which our system of accumulating abstracts for about six months offers the advantage of greater convenience for the user. I, 1980; some older Volume 27 contains literature published in 1980 and received before August literature which was received late and which is not recorded in earlier volumes is also included. We acknowledge with thanks contributions to this volume by Dr. J. Bouska, Prague, who surveyed journals and publications in Czech and supplied us with abstracts in English.

The Hidden Hypotheses Behind the Big Bang It is quite unavoidable that many philosophical a priori assumptions lurk behind the debate between supporters of the Big Bang and the anti-BB camp. The same battle has been waged in physics between the determinists and the opposing viewpoint. Therefore, by way of introduction to this symposium, I would like to discuss, albeit briefly, the many "hypotheses", essentially of a metaphysical nature, which are often used without being clearly stated. The first hypothesis is the idea that the Universe has some origin, or origins. Opposing this is the idea that the Universe is eternal, essentially without beginning, no matter how it might change-the old Platonic system, opposed by an Aristote lian view! Or Pope Pius XII or Abbe Lemaitre or Friedmann versus Einstein or Hoyle or Segal, etc. The second hypothesis is the need for a "minimum of hypotheses" -the sim plicity argument. One is expected to account for all the observations with a mini mum number of hypotheses or assumptions. In other words, the idea is to "save the phenomena", and this has been an imperative since the time of Plato and Aristotle. But numerous contradictions have arisen between the hypotheses and the facts. This has led some scientists to introduce additional entities, such as the cosmologi cal constant, dark matter, galaxy mergers, complicated geometries, and even a rest mass for the photon. Some of the proponents of the latter idea were Einstein, de Broglie, Findlay-Freundlich, and later Vigier and myself.

This volume reviews the current status with respect to both theory and observation of the extragalactic distance scale. A sufficient accuracy is required both for a precise determination of the cosmological parameters and also in order to achieve a better understanding of physical processes in extragalactic systems. The "standard candles", used to set up the extragalactic distance scale, reviewed in this book include cepheid variables, RR Lyrae variables, novae, Type Ia and Type II supernovae as well as globular clusters and planetary nebulae.