The Classification Of Stars

The classification of stars into their various types is one of the fundamental areas of astronomy. This book is a comprehensive handbook on the tools, methods and results of stellar taxonomy. Although this subject is firmly rooted in classical astronomy, vast improvements in observational techniques have transformed the subject and greatly broadened the wavelength regions available for study. The first six chapters describe modern methods of spectroscopic and photometric classification. The remaining nine chapters describe particular families of stars, progressing from the hottest to the coolest. Within each category a description is given of the normal type and all the peculiar stars. Throughout the emphasis is on the phenomenology of classification, rather than the underlying astrophysics. Both authors have devoted themselves to developing the international centre for stellar data at Strasbourg, which uniquely qualifies them to write this definitive handbook for professional astronomers.

Written by leading experts in the field, Stellar Spectral Classification is the only book to comprehensively discuss both the foundations and most up-to-date techniques of MK and other spectral classification systems. Definitive and encyclopedic, the book introduces the astrophysics of spectroscopy, reviews the entire field of stellar astronomy, and shows how the well-tested methods of spectral classification are a powerful discovery tool for graduate students and researchers working in astronomy and astrophysics. The book begins with a historical survey, followed by chapters discussing the entire range of stellar phenomena, from brown dwarfs to supernovae. The authors account for advances in the field, including the addition of the L and T dwarf classes; the revision of the carbon star, Wolf-Rayet, and white dwarf classification schemes; and the application of neural nets to spectral classification. Copious figures illustrate the morphology of stellar spectra, and the book incorporates recent discoveries from earth-based and satellite data. Many examples of spectra are given in the red, ultraviolet, and infrared regions, as well as in the traditional blue-violet optical region, all of which are useful for researchers identifying stellar and galactic spectra. This essential reference includes a glossary, handy appendixes and tables, an index, and a Web-based resource of spectra. In addition to the authors, the contributors are Adam J. Burgasser, Margaret M. Hanson, J. Davy Kirkpatrick, and Nolan R. Walborn.

This classic text - aimed at senior undergraduates and beginning graduate students in physics and astronomy - presents a wide range of concepts in sufficient depth to give the reader a quantitative understanding of the subject. Emphasising physical concepts, it provides the student with a series of astrophysical sketches, concluding with a synthesis of all the subjects discussed in the book, sketching the history of the universe from its beginning to the formation of the Sun and the planets.

Massive stars occupy an exceptional place in general astrophysics. They trigger many if not all of the important processes in galactic evolution whereas due to their intrinsic brightness, they offer the (only until now) possibility to study the stellar content and stellar behaviour in distant galaxies. The last, say, 25 years, massive stars have been the subject of numerous meetings discussing the influence of massive stars on population synthesis, the number distribution of different types of massive stars, the LBV phenomenon, WR stars, X-ray binaries, stellar winds in massive stars, chemical pecularities in massive stars, supernova explosions of massive stars and the important SN1987A event, the influence of massive stars and chemical evolution of galaxies. It is clear that without a theory of stellar evolution, the study of these topics loses a lot of its significance. Massive star evolution therefore got a chance in these meetings, but rarely as a prime subject. The state of the art, the physical processes and the uncertainties in stellar evolution were barely touched. Even more, the influence of close binaries in all these massive star meetings slowly disappeared the last, say, 13 years without any scientific justification, although a significant fraction of stars occurs in close binaries with periods small enough so that both components will interact during their evolution. Denying the binaries or not discussing their influence on results and conclusions, makes the latter very uncertain or even completely unreliable.

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. Volume 18 contains literature published in 1976 and received before March 1, 1977; some older liter ature which was received late and which is not recorded in earlier volumes is also included.

The study of stars and their spectra is central to an understanding of classical and modern astronomy. The principal tool for investigating the nature of stars is to observe and interpret their spectra. In this lucid book, James Kaler clearly explains the alphabet of stellar astronomy - from the cool M stars to hot O stars - and tells the story of the evolution of stars and their place in the Universe. Before embarking on a fascinating voyage of cosmic discovery, we are introduced to the fundamental properties of stars, and how they can be categorised. Next, the structure of atoms and the formation of spectra is discussed, as a prelude to a full description of the spectral classification itself. The heart of the book examines each star type in turn and explores their spectra in detail. Notable discoveries and features related to each class sustain the story. There is also a review of unusual stars that cannot easily be classified. Finally, the book closes with a skilful integration of all the data - tracing the paths of birth, life and death of stars on the Hertzsprung-Russell diagram. This book is based on a widely acclaimed series of articles on stellar astronomy which appeared in the magazine Sky and Telescope. It provides an invaluable introduction for observers and students.

This book will bring together experts in the field of astronomical photometry to discuss how their subfields provide the precision and accuracy in astronomical energy flux measurements that are needed to permit tests of astrophysical theories. Differential photometers and photometry, improvements in infrared precision, the improvements in precision and accuracy of CCD photometry, the absolute calibration of flux, the development of the Johnson UBVRI photometric system and other passband systems to measure and precisely classify specific types of stars and astrophysical quantities, and the current capabilities of spectrophotometry, and polarimetry to provide precise and accurate data, will all be discussed in this volume. The discussion of `differential’ or `two-star’ photometers will include those developed for planetary as well as stellar photometry and will range from the Princeton polarizing photometer through the pioneering work of Walraven to the differential photometers designed to measure the ashen light of Venus and to counter the effects of aurorae at high latitude sites; the last to be discussed will be the Rapid Alternate Detection System (RADS) developed at the University of Calgary in the 1980s.

''A clear and comprehensive introduction to contemporary philosophy of science.'' -- American Scientist ''The best account of scientific theory now available, one that surely commends itself to every philosopher of science with the slightest interest in metaphysics.'' -- Review of Mathematics ''It should certainly be of interest to those teaching graduate courses in philosophy of science and to scientists wishing to gain a further appreciation of the approach used by philosophers of science.'' -- Science Activities

This star guide enables astronomers to choose a class of object, and for any month of the year find an observation list that begins with the easiest through to progressively more difficult targets. Following detailed descriptive summaries of each class of object, it includes extensive lists of deep-sky targets which are classified according to type of object. Amateur astronomers of all levels will find this book invaluable for its broad-ranging background material, its lists of fascinating objects, and for its power to improve practical observing skills while viewing many different types of deep-sky objects.

The contributions in this volume represent the latest research results in the field of Classification, Clustering, and Data Analysis. Besides the theoretical analysis, papers focus on various application fields as Archaeology, Astronomy, Bio-Sciences, Business, Electronic Data and Web, Finance and Insurance, Library Science and Linguistics, Marketing, Music Science, and Quality Assurance.

This volume contains the fifteenth tri-annual reports of the Presidents of the forty Commissions of the International Astronomical Union; it refers to the progress in our discipline during the three years 1970, 1971 and 1972. As compared to earlier volumes a gradual change in character is unmistakable. The ever increasing flow of publications, combined with the obvious necessity to keep the Reports at a reasonable size and price level has gradually forced the Commission Presidents to be more selective than before in drafting their Reports. I have certainly stimulated them into that direction - in order that Reports like these be valuable and lasting, it seems imperative that the individual contributions have the character of a critical overall review, where a fairly complete summary is given of the major develop ments and discoveries of the past three years, and in which the broad developments and new trends be clearly outlined, while at the same time essential problems for future research are identified. With respect to the latter item I have suggested the Commission Presidents to add to their reports a brief section on scientific priorities for future research in the field of their Commissions. In order to save space I have suggested to Commission Presidents that references to published papers are given on the basis of their number in the published issues of Astronomy and Astrophysics Abstracts. For instance, the indication (06. 078. 019) or (AAA 06. 078.

"Ethical Choices in Contemporary Medicine" jettisons the standard medical ethics models of "rights" language and shows how the bioethical problems that receive attention from the media and the public are related to and are explicable in terms of the epistemological foundations of science and medicine. These epistemological concerns include how medical knowledge is established (scientific validity), how medical protocols are administered (checks and balances), how medical certainty is evaluated (probability) and medical responsibility is framed (personal or collective), and how medical knowledge is transmitted (popular media versus professional journals) and how medical care is allocated (insurance policies and government subsides). The book examines the present predicaments of medicine within a broad cultural context and suggests that rational discourse and parochial ethical dialogue may be futile in the face of competing and incommensurable frameworks and agendas, attitudes and wishes. The authors show that, in the postmodern age, two interrelated issues surface when it comes to medicine. On the one hand, there is a strong critique of science and the privileges associated with the scientific discourse and, on the other, there is still a deep-seated quest for certainty in all medical matters.

The definitive history of humanity's search to find its place within the universe. North charts the history of astronomy and cosmology from the Paleolithic period to the present day.