Download or read book Abundances of Elements in Stars and Nebulae Studies of hydrogen deficient stars I written by Lawrence Hugh Aller and published by . This book was released on 1962 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Hydrogen Deficient Stars and Related Objects written by K. Hunger and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first helium star was discovered in 1942, the first scientific meeting on the subject, however, took place in 1985. The meeting was hence long overdue for, in the meantime, a substantial amount of material had been accumulated by a rather small, but active scientific community. Hence, it appeared necessary to review the field in order to define the subject, assess its present status and discuss future developments. Hydrogen deficiency is a widespread phenomenon, occurring in a large variety of stellar and nonstellar objects. It can be readily detected in B stars as these exhibit both hydrogen and helium lines, if the elements are present in appreciable amounts. It becomes less manifest in cool stars, where the temperature is too low to excite helium and where one has to devise indirect methods for proving hydrogen deficiency. Clearly, it was not possible to discuss the whole complex of hydrogen deficiency, i.e. in both stars and diffuse matter, but rather to concentrate on the issue of helium stars.

Download or read book Abundances of Elements in Stars and Nebulae written by Lawrence Hugh Aller and published by . This book was released on 1962 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: Contents: Energy distribution in globular star clusters Data for southern globular clusters Measurements of the energy distributions in southern globular clusters Spectrophotometry of the Wolf-Rayet star of gamma 2 velorum The hydrogen/helium ratio in HD 96446 The emission nebulosities in the large Magellanic cloud Emission nebulosities in the small Magellanic cloud Photographic region of the spectrum of NGC 7009 Report on research carried out at the University of Michigan and supported by the U.S.A.F. under Contract No. AF 49(638)807.

Download or read book Abundances of Elements in Stars and Nebulae written by Lawrence Hugh Aller and published by . This book was released on 1962 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Abundances of Elements in Stars and Nebulae the Abundance of Certain Elements in the Solar Atmosphere written by and published by . This book was released on 1962 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The chemical composition of the Manganese star 53 Tauri was studied with the aid of data secured with the coude spectrograph of the 120-inch reflector at the Lick Observatory. Transition probabilities required for the problem are obtained from laboratory sources whenever possible, but some are obtained by the calibration of stellar data. The temperature of the star, deduced from ionization equilibrium, is near 11,000K-a value in good agreement with that found from spectral energy scans by Jugaku and Sargent. The electron pressure in the atmosphere, deduced from the total intensities of hydrogen lines, appears to lie in the neighborhood of 500 dynes sq cm. Several striking abundance anomalies are found; they cannot be explained by deviations from local thermodynamic equilibrium. Manganese seems to be the most abundant metal in the star, but gallium appears to show the greatest enhancement of abudance over the 'normal' value. Strontium, yttrium, and zirconium are also enhanced in abudnace, whilst magnesium, and calcium seems to be depleted. (Author).

Download or read book Hydrogen deficient stars proceedings of a workshop held at Eberhard Karls University T bingen Germany 17 21 September 2007 written by Klaus Werner and published by . This book was released on 2008 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: "These are the proceedings of a conference on Hydrogen-Deficient Stars held at the University of Tübingen, Germany, from September 17-21 2007. This conference was the third in a series of international colloquia on this topic. The first one took place in Mysore, India in 1985, and the second one a decade alter, 1995 in Bamberg, Germany. Twelve years later it was considered useful to gather again to discuss the progress and the future directions in this field. At the conference 68 participants from 20 countries presented 25 invited talks, 27 contributed talks, and 16 posters. Hydrogen-deficiency is exhibited by many evolved high-and low-mass stars. Therefore research on hydrogen-deficient stars is quite diverse since such stars are found in almost every region of the Hertzsprung-Russell diagram. The stellar classes discussed in detail at the conference were: R Coronae Borealis stars, extreme helium stars, Wolf-Rayet central stars of planetary nebulae, PG 1159 stars and related objects, white dwarfs of spectral type DO, DB, and DQ, and helium-rich subdwarf O and B stars. Also highlighted were hydrogen-deficient stars in close binary systems (AM Cvn and ultracompact low-mass X-ray binaries), massive Wolf-Rayet Stars and their relation to Type I supernovae and Gamma-ray bursts. The different classes of objects discussed in this volume are grouped by spectral and pulsational characteristics, by evolutionary scenarios such as late helium flashes and double-degenerate mergers, and by links among the classes."--Publisher's website.

Download or read book U S Government Research Reports written by and published by . This book was released on 1962 with total page 1170 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Abundances of Elements in Stars and Nebulae The Abundance of Certain Elements in the Solar Atmosphere written by L. E. Aller and published by . This book was released on 1962 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Abundance of the Elements written by Lawrence Hugh Aller and published by . This book was released on 1961 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Technical Publications Announcements with Indexes written by United States. National Aeronautics and Space Administration and published by . This book was released on 1962 with total page 1556 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Keywords Index to U S Government Technical Reports written by United States. Department of Commerce. Office of Technical Services and published by . This book was released on 1962 with total page 990 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Keywords Index to U S Government Technical Reports permuted Title Index written by United States. Department of Commerce. Office of Technical Services and published by . This book was released on 1962 with total page 860 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A New Interpretation of the Heavy Element Abundances in Metal deficient Stars written by James W. Truran and published by . This book was released on 1980 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book AFOSR written by United States. Air Force. Office of Scientific Research and published by . This book was released on 1968 with total page 968 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1974 with total page 1064 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fundamental Questions in Astrophysics Guidelines for Future UV Observatories written by Ana I. Gómez de Castro and published by Springer Science & Business Media. This book was released on 2007-01-30 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modern astrophysics has evolved early phases of discovery and classification to a physics-oriented quest for answers to fundamental problems from cosmology to the origin and diversity of life-sustainable systems in the Universe. Future progress in modern astrophysics requires access to the electromagnetic spectrum in the broadest energy range. This book describes the fundamental problems in modern astrophysics that cannot progress without easy and wide-spread access to modern UV instrumentation.

Download or read book Literature 1973 Part 1 written by Siegfried Böhme and published by Springer Science & Business Media. This book was released on 2013-03-14 with total page 618 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 9 contains literature published in 1973 and received before August 15, 1973; some older liter ature 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, who surveyed journals and publications in the Czech language and supplied us with abstracts in English, and by the Common wealth Scientific and Industrial Research Organization (C.S.I.R.O.), Sydney, for providing titles and abstracts of papers on radio astronomy.