Download or read book The Evolution of Helium White Dwarfs written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Evolution of Helium White Dwarfs written by and published by . This book was released on 1999 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Evolution of Helium White Dwarfs written by and published by . This book was released on 1999 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book White Dwarfs written by G. Vauclair and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt: The European Workshop on White Dwarfs was initiated by Prof. V. Weidemann, with the first meeting organized in Kiel (FRG) in 1974. Almost every two years, an increasing number of astronomers met to share their results and projects in the subsequent workshops: Frascati (1976), Tel Aviv (1978), Paris (1981), Kiel (1984), Frascati (1986). In the mean time, two major IAU colloquia (No. 53 in Rochester, NY, 1979; and No. 114 in Hanover, NH, 1988) emphasized the importance of these stars for our understanding of stellar evolution. The informal organization of the white dwarf community has been the starting point for large cooperative projects of which the Hubble Space Telescope "White Dwarf Consortium" and the "Whole Earth Telescope" are the most spectacular examples. But many other successful collaborations have also been born during the very exciting discussions conducted in the last 16 years on the occasion of our regular meetings. The 7th European Workshop on White Dwarfs took place the year of the seventieth birthday of Prof. Evry Schatzman, whose pioneering work has been the inspiration for many of the new ideas in the white dwarf community. The Scientific Organizing Committee has agreed to dedicate the workshop to him on this occasion. We are pleased to publish as an introduction to the workshop, the text of the talk delivered by Prof. Schatzman at the workshop's banquet.
Download or read book The Evolution of Helium White Dwarfs written by and published by . This book was released on 2000 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Evolution of Helium White Dwarfs written by and published by . This book was released on 1998 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Red Giants and White Dwarfs written by Robert Jastrow and published by . This book was released on 1979 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: "A masterpiece of science."-Werner von Braun.
Download or read book Evolution of Helium Star white Dwarf Binaries Leading Up to Thermonuclear Supernovae written by Tin Long Sunny Wong and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Thermonuclear supernovae are believed to be explosions of carbon-oxygen white dwarfs (CO WDs), but how these CO WDs reach explosion conditions remains debated. In this project we study the helium donor channel which involves a CO WD growing in mass through accretion from a nondegenerate helium star and exploding when it approaches the critical Chandrasekhar mass."--Page [iii]
Download or read book Red Giants and White Dwarfs written by Robert Jastrow and published by . This book was released on 1967 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Observations and Theory of Pulsating Helium White Dwarfs written by Justin D. Steinfadt and published by . This book was released on 2011 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: Average C/O-core white dwarf stars pulsate in observable normal modes of oscillation with amplitudes of a few percent and periods of 100--1,000 seconds. As of this dissertation, no WD of less than 0.5 Msun has been observed to pulsate. White dwarfs of this low mass likely possess a He core and are products of very different stellar evolution. In this dissertation, we have constructed very low mass He-core WD models and predict the parameter space in which they may be observed to pulsate. We have also observed 13 stars, most of which are He-core WDs, in a search for the first He-core WD pulsator. While we were unsuccessful in discovering a pulsator, our detection limits offer unique constraints on He-core WD pulsation parameter space. As a fortuitous result of our pulsation search, we have discovered two unique eclipsing binary systems. One of these is the first eclipsing detached double white dwarf binary system offering the first opportunity to make model independent constraints on He-core WD models and evolution.
Download or read book Helium Shell Flashes and Evolution of Accreting White Dwarfs written by Masayuki Y. Fujimoto and published by . This book was released on 1982 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nonradial Oscillations of Stars written by Wasaburō Unno and published by . This book was released on 1989 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Structure And Evolution Of Stars written by Eldridge J J and published by World Scientific. This book was released on 2018-12-06 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stars are the fundamental observable constituents of the Universe. They are the first objects we see in the night sky, they dominate the light produced in our own and other galaxies, and nucleosynthesis in stars produces all the elements heavier than helium. A knowledge of stars and their evolution is vital to understand other astrophysical objects from accreting black holes and galaxies to the Universe itself.The structure of a star can be described mathematically by differential equations derived from the principles of hydrodynamics, electromagnetic theory, thermodynamics, quantum mechanics, atomic and nuclear physics. The basic equations of a spherical star are derived in detail at an accessible level. The topics discussed include modes of energy transport, the equation of state, the physics of the opacity sources and the nuclear reactions. Attention is also given to the virial theorem, polytropic gas spheres and homology principles and the procedure for numerical solution of the equations is outlined. This book tracks the evolution of stars from their main-sequence evolution through the exhaustion of various nuclear fuels to the end points of evolution and also introduces the topic of interacting binary stars. The aim is to take the reader from the essential underlying physical principles to the doors to current research on stellar interiors.
Download or read book Evolutionary Models of White Dwarfs with Helium Cores written by and published by . This book was released on 1998 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Interstellar Grains written by Chandra Wickramasinghe and published by . This book was released on 1967 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book White Dwarfs Cosmological and Galactic Probes written by E. Sion and published by Springer Science & Business Media. This book was released on 2005-08-25 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: The emphasis on white dwarf stars and cosmology arises from the most recent advances in cosmological and galactic structure research in which white dwarf stars are playing a very prominent role. Examples are Type Ia supernovae (i.e. white dwarf supernovae), the origin and evolution of the universe, the age of the galactic disk, cosmochronology using white dwarfs in globular clusters and galactic clusters, and the physics of accretion onto compact (very dense) stars. As an assisting guide to the reader, we have included, by invitation, comprehensive review articles in each of the four major areas of the book, white dwarf supernovae, cosmology, accretion physics and galactic structure. The reviews include introductory material that they build upon. The book is suitable and most useful to advanced undergraduates, graduate students and scientific professionals (e.g. astronomers, astrophysicists, cosmologists, physicists).
Download or read book On the Spectral Evolution of Cool Helium Atmosphere White Dwarfs Detailed Spectroscopic and Photometric Analysis of DZ Stars written by and published by . This book was released on 2007 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a detailed analysis of a large spectroscopic and photometric sample of DZ white dwarfs based on our latest model atmosphere calculations. We revise the atmospheric parameters of the trigonometric parallax sample of Bergeron, Leggett, & Ruiz (12 stars) and analyze 147 new DZ white dwarfs discovered in the SDSS. The inclusion of metals and hydrogen in our model atmosphere calculations leads to different atmospheric parameters than those derived from pure helium models. Calcium abundances are found in the range from log (Ca/He) = -12 to -8. We also find that fits of the coolest objects show peculiarities, suggesting that our physical models may not correctly describe the conditions of high atmospheric pressure encountered in the coolest DZ stars. We find that the mean mass of the 11 DZ stars with trigonometric parallaxes is significantly lower than that obtained from pure helium models and in much better agreement with the mean mass of other types of white dwarfs. We determine hydrogen abundances for 27% of the DZ stars in our sample, while only upper limits are obtained for objects with low-S/N spectroscopic data. We confirm with a high level of confidence that the accretion rate of hydrogen is at least 2 orders of magnitude smaller than that of metals (and up to 5 in some cases) to be compatible with the observations. We find a correlation between the hydrogen abundance and the effective temperature, suggesting for the first time empirical evidence of a lower temperature boundary for the hydrogen screening mechanism. Finally, we speculate on the possibility that the DZA white dwarfs could be the result of the convective mixing of thin hydrogen rich atmospheres with the underlying helium convection zone.
