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Author: R. Szczerba
Publisher: Springer Science & Business Media
ISBN: 9401596883
Category : Science
Languages : en
Pages : 457
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Book Description
The term proto-planetary nebulae (PPNe) in the context of the late stages of stellar evolution was created only slightly more than 20 years ago to express the belief that in the near future these objects will become planetary nebulae (PNe). The first proto-planetary nebulae (called also post-Asymptotic Giant Branch, or shortly post-AGB objects) AFGL 2688 and AFGL 618 were discovered in mid seventies in course of the Air Force Sky Survey. Investigation of this phase of stellar evolution developed very rapidly in 1980's after the IRAS mission when it became clear that proto-planetary nebulae emit a significant part of their energy in the mid-and far-infrared. Hundreds of new candidates have been proposed but the recognition of the real proto-planetary nebulae is not a simple task and needs a substantial effort to exclude cases that represent different evolutionary stages. High resolution spectroscopy of stellar atmospheres is of much importance in this respect. Surprisingly, only a small group of central stars, the so called 21 11m emitters, show chemical signatures of the 3 rd dredge up process. Very recently, a more detailed studies of mid-infrared spectra from the Infrared Space Observatory (ISO) allow for a better understanding of chemical composition and evolution of circumstellar material around these stars. A new impetus in the field of proto-planetary nebulae research was started in the 1990's with high spatial resolution imaging in mid-infrared and optical wavelength ranges.
Author: R. Szczerba
Publisher: Springer Science & Business Media
ISBN: 9780792371458
Category : Medical
Languages : en
Pages : 480
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Book Description
The term proto-planetary nebulae (PPNe), in the context of the late stages of stellar evolution, was created just over 20 years ago, to express the belief that in the near future these objects will become planetary nebulae (PNe). The first proto-planetary nebulae (also called post-Asymptotic Giant Branch or post-AGB objects) were discovered in the mid-1970s in the course of the Air Force Sky Survey. Investigation of this phase of stellar evolution developed very rapidly in the 1980s after the IRAS mission when it became clear that proto-planetary nebulae emit a significant part of their energy in the mid- and far-infrared. A new impetus in this field began in the 1990s with high spatial resolution imaging in mid-infrared and optical wavelengths. Evidence has been found that proto-planetary nebulae (at least their central parts) are quite asymmetric while shells of AGB stars display spherical shapes. The most intriguing challenge now is to understand which physical processes are dominant during formation and evolution of proto-planetary nebulae. Is it magnetic field, evolution in binary systems, planets, axisymmetric superwind mass loss and its further shaping by fast wind, collimated jets interacting with a spherically symmetric AGB remnant or maybe an interplay between these different processes? Another challenge is to explain why the mass loss process near the end of the AGB evolution is modulated on timescales of a few hundred years. The model presented during this workshop seems to be very promising in this respect.
Author: Harm J. Habing
Publisher: Springer Science & Business Media
ISBN: 1475738765
Category : Science
Languages : en
Pages : 566
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Book Description
The underlying astrophysical mechanisms of the objects known as asymptotic giant branch stars - the structures that occur during the dramatic period prior to a star's death - is the main theme of this text. Over the past three decades, asymptotic giant branch stars have become a topic of their own, and the contributions to this volume all focus on these entities themselves, rather than their connections to other fields of astronomy. Among the many topics covered are new methods of high- quality infrared observation and the more detailed and realistic simulations made possible by increasingly fast computers. This collection should be useful to graduate students who work in the field, teachers who want to address the subject in their courses, and to astronomers from various backgrounds who are interested in the astrophysics of AGB stars.
Author: R. Szczerba
Publisher: Springer Science & Business Media
ISBN: 9401596883
Category : Science
Languages : en
Pages : 457
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Book Description
The term proto-planetary nebulae (PPNe) in the context of the late stages of stellar evolution was created only slightly more than 20 years ago to express the belief that in the near future these objects will become planetary nebulae (PNe). The first proto-planetary nebulae (called also post-Asymptotic Giant Branch, or shortly post-AGB objects) AFGL 2688 and AFGL 618 were discovered in mid seventies in course of the Air Force Sky Survey. Investigation of this phase of stellar evolution developed very rapidly in 1980's after the IRAS mission when it became clear that proto-planetary nebulae emit a significant part of their energy in the mid-and far-infrared. Hundreds of new candidates have been proposed but the recognition of the real proto-planetary nebulae is not a simple task and needs a substantial effort to exclude cases that represent different evolutionary stages. High resolution spectroscopy of stellar atmospheres is of much importance in this respect. Surprisingly, only a small group of central stars, the so called 21 11m emitters, show chemical signatures of the 3 rd dredge up process. Very recently, a more detailed studies of mid-infrared spectra from the Infrared Space Observatory (ISO) allow for a better understanding of chemical composition and evolution of circumstellar material around these stars. A new impetus in the field of proto-planetary nebulae research was started in the 1990's with high spatial resolution imaging in mid-infrared and optical wavelength ranges.
Author: Robert T. Rood
Publisher: Cambridge University Press
ISBN: 9780521591843
Category : Science
Languages : en
Pages : 368
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Book Description
An understanding of how stars evolve is central to astrophysics. The basic theory is well established. However, the subject has undergone a renaissance in recent years as powerful computers have become widely available and allowed complex evolutionary models to be developed and compared in great detail with observations from the latest instruments. This timely volume presents the review articles from an international meeting in Elba, Italy, where experts gathered to review how our understanding of stellar evolution has advanced. Topics covered include fundamentals of stellar evolution, star clusters, variable stars, asymptotic giant branch stars, degenerate stars, the evolution of binary stars, and chemical and galactic evolution. Throughout, theory and observation are closely compared. The book also emphasises the critical role stars have on our understanding of how galaxies evolve. In this book we are provided with both the fundamentals and the latest research. In this way, it will provide an invaluable supplement for graduate students, and a timely review for researchers.
Author: L.B.F.M. Waters
Publisher: Springer Science & Business Media
ISBN: 9780792351528
Category : Science
Languages : en
Pages : 562
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Book Description
This conference proceedings contains review papers and contributed papers discussing early results from the Infrared Space Observatory (ISO) on the subject of stellar evolution. Three topics have been emphasized in the book: young stellar objects and Vega-type stars, circumstellar matter of massive stars, and late stages of stellar evolution. The very rich harvest of new results from ISO is demonstrated by the many discoveries of new solid state and molecular bands in the spectra of stars and circumstellar shells, and by spectacular images of circumstellar and interstellar matter. The book is intended for professional astronomers and students.
Author: R. Szczerba
Publisher:
ISBN:
Category :
Languages : en
Pages : 23
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Book Description
Author: M. O. Mennessier
Publisher: Atlantica Séguier Frontières
ISBN: 9782863320778
Category : Astronomical masers
Languages : en
Pages : 598
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Book Description
Author: Brian Davis
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Great strides have been made in recent years to better understand the late stages of stellar evolution for low- and intermediate-mass stars, and, specifically, the asymptotic giant branch (AGB) and post-AGB (PAGB) phases. Even still, there is a great amount of work to be done, as large discrepancies between theory and observations remain. In this dissertation, I perform observational studies of pre- and post-AGB stellar evolution for stars in this mass range, so as to provide better constraints for future theoretical models. For stars with masses 2 Msun, the horizontal-branch (HB) is the phase of evolution immediately preceding the AGB. Stars lying above the HB in the color-magnitude diagrams (CMDs) of globular clusters (GCs) offer valuable observational tests of theoretical evolutionary tracks. I therefore compiled what is to date the most complete survey of above-horizontal-branch (AHB) stars--objects lying above the HB and blueward of the AGB in the CMD--in 97 Galactic and seven Magellanic Cloud GCs. I selected AHB candidates based on photometry in the uBVI system, which is optimized for detection of low-gravity stars with large Balmer jumps, in the color range -0.05 (B-V)_0
Author: International Astronomical Union. Colloquium
Publisher: Cambridge University Press
ISBN: 9780521366175
Category : Science
Languages : en
Pages : 464
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Book Description
Red giant stars are evolutionarily advanced objects in the closing stages of their nuclear burning lifetime. Observed with increasing spectral coverage they display a variety of unusual phenomena. Many are characterized by peculiar (non-solar) surface chemical compositions which provide otherwise unobtainable clues to interior nucleosynthesis, mixing and evolution. Others may have received their chemical peculiarities by mass transfer from a companion. This book reports on the proceedings of the International Astronomical Union Colloquium 106. It contains discussions on many aspects of these stars, combining theory and observation to interpret these objects in terms of their evolutionary history. There are 20 review papers, 69 abstracts and short contributed papers and a complete transcript of the valuable summary panel discussion. Professional astronomers will find this book useful as a reference work which incorporates current research on the modelling and evolution of these unstable stars.
Author: Amanda I. Karakas
Publisher:
ISBN:
Category :
Languages : en
Pages : 9
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Book Description
