The Effects of Rotation on the Winds from Hot Stars
Author : Jon Eric Bjorkman
Publisher :
Page : 380 pages
File Size : 10,72 MB
Release : 1992
Category :
ISBN :
Author : Jon Eric Bjorkman
Publisher :
Page : 380 pages
File Size : 10,72 MB
Release : 1992
Category :
ISBN :
Author : Clint Horton Poe
Publisher :
Page : 354 pages
File Size : 16,36 MB
Release : 1987
Category :
ISBN :
Author : L.A. Willson
Publisher : Springer Science & Business Media
Page : 366 pages
File Size : 21,24 MB
Release : 2012-12-06
Category : Science
ISBN : 9400921055
Fundamental unsolved problems of stellar astrophysics include the effects of angular momentum on stellar structure and evolution, the nature and efficiency of the processes by which angular momentum is redistributed within and lost from stars, and the role that stellar rotation plays in enhancing or driving stellar mass loss. There appears to be a qualitative change in the nature and efficiency of these mechanisms near spectral type FO: hotter (more massive) stars typically retain more angular momentum at least until they reach the main sequence, while cooler stars typically spin down quickly. For the hotter stars, recent work suggests a strong link between the type of pulsation behavior, the mass loss rates, and the rotation velocity. If the same mechanisms are able to drive mass loss from the main sequence A stars, as has recently been proposed, then the current interpretations of a number of observations will be drastically affected: e. g. the ages of clusters may be incorrect by up to a factor of two, and the surface abundances of isotopes of He, Li and Be may no longer give constraints on cosmological nucleosynthesis. There are also effects on the evolution of the abundances of elements in the interstellar medium and on the general evolution of populations of stars. Thus the questions of the mechanisms of angular momentum and mass loss of stars more massive than the sun is important not only for stellar studies but for the foundations of much of modern astrophysics.
Author : Anthony F.J. Moffat
Publisher : Springer Science & Business Media
Page : 475 pages
File Size : 18,75 MB
Release : 2012-12-06
Category : Science
ISBN : 9401103151
This specialized workshop was conceived during the workshop on "Non isotropic and Variable Outflows from Stars", which was held at the Space Telescope Science Institute in October, 1991. At that meeting, the four of us collectively decided that the time was ripe for an even more focussed discussion of the basic issues in the area of hot-star wind instability and its observable manifestations. Not that the big problems have been solved! Rather, we are currently in a phase of rapid development, both with regard to the models and to the observations. The key issue at this new workshop would be to decide how the time-dependent structures observed in hot-star winds (e. g. , NACs, DACs, blobs, clumps, filaments, shells, puffs, jets, etc. ) relate to radiative and other instabilities. Further questions concern the role of turbulence and the nature of its driver, and the effect of stellar rotation, pulsation, and magnetic fields on time-dependent phenomena in hot-star winds. Of no less importance is the impact of stellar wind variability on the derivation of mass-loss rates, on stellar evolution, and on momentum/energy deposition in the interstellar medium. To attain our goal of maximum confrontation (in the positive sense!) we decided: (1) to limit the workshop to the observers and theoreticians most active in this field in the world; (2) to insist that virtually all participants present a talk, thereby avoiding the distraction of poster sessions; and (3) to allocate approximately half of the allotted time to discussion.
Author : Asif Ud-Doula
Publisher :
Page : 380 pages
File Size : 16,39 MB
Release : 2002
Category : Magnetohydrodynamics
ISBN :
Author : Henny J. G. L. M. Lamers
Publisher : CRC Press
Page : 342 pages
File Size : 13,60 MB
Release : 2018-02-28
Category : Stars
ISBN : 9780750312790
'Understanding Stellar Evolution' is based on a series of graduate-level courses taught at the University of Washington since 2004, and is written for physics and astronomy students and for anyone with a physics background who is interested in stars. It describes the structure and evolution of stars, with emphasis on the basic physical principles and the interplay between the different processes inside stars such as nuclear reactions, energy transport, chemical mixing, pulsation, mass loss, and rotation. Based on these principles, the evolution of low- and high-mass stars is explained from their formation to their death. In addition to homework exercises for each chapter, the text contains a large number of questions that are meant to stimulate the understanding of the physical principles. An extensive set of accompanying lecture slides is available for teachers in both Keynote(R) and PowerPoint(R) formats.
Author : Jean-Pierre Rozelot
Publisher : Springer Science & Business Media
Page : 266 pages
File Size : 50,65 MB
Release : 2009-01-08
Category : Science
ISBN : 3540878300
The Sun and stars rotate in di?erent ways and at di?erent velocity rates. The knowledge of how they rotate is important in understanding the formation and evolution of stars and their structure. The closest star to our Earth, the Sun, is a good laboratory to study in detail the rotation of a G star and allows to test new ideas and develop new techniques to study stellar rotation. More or less massive, more or lessevolved objects, however, can have averydi?erent rotation rate, structure and history. In recent years our understanding of the rotation of the Sun has greatly improved. The Sun has a well-known large-scale rotation, which can be m- sured thanks to visible features across the solar disk, such as sunspots, or via spectroscopy. In addition, several studies cast light on di?erential rotation in the convective zone and on meridional circulation in the radiative zone of the Sun. Even the rotation of the core of the Sun can now be studied thanks to various methods, such as dynamics of the gravitational moments and of course, helioseismology, through g-modes analysis. Moreover, the magnetic ?eld is strongly linked to the matter motions in the solar plasma. The solar magnetic ?eld can be measured only at the surface or in theupperlayers.Itistheproductoftheinternaldynamoorofthelocaldynamos if they exist – in any case magnetic ?eld and rotation cannot thus be separated.
Author : Anne Barbara Underhill
Publisher :
Page : 268 pages
File Size : 38,89 MB
Release : 1985
Category : Early stars
ISBN :
Author : Wolf-Rainer Hamann
Publisher : Universitätsverlag Potsdam
Page : 262 pages
File Size : 47,95 MB
Release : 2008
Category : Stellar winds
ISBN : 3940793337
Author : Ka Lok Cheng
Publisher : Springer Science & Business Media
Page : 360 pages
File Size : 16,57 MB
Release : 2003-11-30
Category : Science
ISBN : 9781402016837
The Pacific Rim Conferences for the first decade from the mid 1980's to the mid 1990's were primary concerned with binary stars research. The Conference expanded to all areas of Stellar Astrophysics for the last two meetings in Hong Kong; at Hong Kong University of Science and Technology in 1997 and at the Hong Kong University in 1999. At the conclusion of the very successful Pacific Rim Conference on Stellar Astrophysics held in Hong Kong University, members of the Sci entific Organizing Committee began planning for the next conference. We approached Professor Tan Lu of Nanjing University and Professor Tipei Li of the Institute of High Energy Physics about hosting a con ference in China. The city of Xi'an in Shaanxi province and a city in Yunnan province, were considered to be the most likely locations. It be came crucial to find the right person to serve as Chair (or Co-chairs) for the Local Organizing Committee. Initially, Professor Lu was the logical choice but he declined for personal reasons. Professor Li was invited to lead a new department of Astrophysics at Tsinghua University so he could not take on the additional load of chairing the LOC. Professor Gang Zhao of Beijing Astronomical Observatory was approached to take on the task but he also declined. This has been a busy time for Chinese astronomers. The SOC decided to have the conference dedicated to honor Dr. Helmut A.