The Rotation of Sun and Stars

The Rotation of Sun and Stars PDF

Author: Jean-Pierre Rozelot

Publisher: Springer Science & Business Media

Published: 2009-01-08

Total Pages: 266

ISBN-13: 3540878300

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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.

Studying Stellar Rotation and Convection

Studying Stellar Rotation and Convection PDF

Author: Mariejo Goupil

Publisher: Springer

Published: 2012-12-15

Total Pages: 265

ISBN-13: 364233380X

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This volume synthesizes the results of work carried out by several international teams of the SIROCO (Seismology for Rotation and Convection) collaboration. It provides the theoretical background required to interpret the huge quantity of high-quality observational data recently provided by space experiments such as CoRoT and Kepler. Asteroseismology allows astrophysicists to test, to model and to understand stellar structure and evolution as never before. The chapters in this book address the two groups of topics summarized as "Stellar Rotation and Associated Seismology" as well as "Stellar Convection and Associated Seismology". The book offers the reader solid theoretical background knowledge and adapted seismic diagnostic techniques.

Stellar Rotation

Stellar Rotation PDF

Author: Jean-Louis Tassoul

Publisher: Cambridge University Press

Published: 2000-04-13

Total Pages: 274

ISBN-13: 1139428322

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Like the Earth and planets, stars rotate. Understanding how stars rotate is central to modelling their structure, formation and evolution, and how they interact with their environment and companion stars. This authoritative volume, first published in 2000, provides a lucid introduction to stellar rotation and the definitive reference to the subject. It combines theory and observation in a comprehensive survey of how the rotation of stars affects the structure and evolution of the Sun, single stars and close binaries. This book will be of primary interest to graduate students and researchers studying solar and stellar rotation and close binary systems. It will also appeal to those with a more general interest in solar and stellar physics, star formation, binary stars and the hydrodynamics of rotating fluids - including geophysicists, planetary scientists and plasma physicists.

Differential Rotation in Sun-like Stars from Surface Variability and Asteroseismology

Differential Rotation in Sun-like Stars from Surface Variability and Asteroseismology PDF

Author: Martin Bo Nielsen

Publisher: Springer

Published: 2017-01-24

Total Pages: 110

ISBN-13: 3319509896

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In his PhD dissertation Martin Bo Nielsen performs observational studies of rotation in stars like the Sun. The interior rotation in stars is thought to be one of the driving mechanisms of stellar magnetic activity, but until now this mechanism was unconstrained by observational data. NASA’s Kepler space mission provides high-precision observations of Sun-like stars which allow rotation to be inferred using two independent methods: asteroseismology measures the rotation of the stellar interior, while the brightness variability caused by features on the stellar surface trace the rotation of its outermost layers. By combining these two techniques Martin Bo Nielsen was able to place upper limits on the variation of rotation with depth in five Sun-like stars. These results suggest that the interior of other Sun-like stars also rotate in much the same way as our own Sun.

SCORe ’96: Solar Convection and Oscillations and their Relationship

SCORe ’96: Solar Convection and Oscillations and their Relationship PDF

Author: F.P. Pijpers

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 311

ISBN-13: 9401151679

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This volume contains the reviews and poster papers presented at the workshop Solar Convection and Oscillations and their Relationship: SCORe '96, held in Arhus, Denmark, May 27 - 31, 1996. The aim of this workshop was to bring together experts in the fields of convection and helioseismology, and to stimulate collaborations and joint research. The participation to this workshop was purposely kept limited in order to provide optimal conditions for informal discussions. In autumn of 199,5 the long-awaited GONG network of solar telescopes became fully operational and the first data already show significant improvement over existing datasets on solar oscillations. Furthermore, in December of 1995 the satellite SOHO was launched which, together with GONG, provides a major step forward in both the quantity and the quality of available solar oscillation data. It is with this in mind that we decided to organize the workshop to prepare for the optimal use of this wealth of data, with which to deepen our understanding of solar structure and specifically, of one of the longest-standing problems in solar and stellar modelling: the treatment of convection.

The Solar Tachocline

The Solar Tachocline PDF

Author: D. W. Hughes

Publisher: Cambridge University Press

Published: 2007-05-31

Total Pages: 369

ISBN-13: 113946258X

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Helioseismology has enabled us to probe the internal structure and dynamics of the Sun, including how its rotation varies in the solar interior. The unexpected discovery of an abrupt transition - the tachocline - between the differentially rotating convection zone and the uniformly rotating radiative interior has generated considerable interest and raised many fundamental issues. This volume contains invited reviews from distinguished speakers at the first meeting devoted to the tachocline, held at the Isaac Newton Institute. It provides a comprehensive account of the understanding of the properties and dynamics of the tachocline, including both observational results and major theoretical issues, involving both hydrodynamic and magnetohydrodynamic behaviour. The Solar Tachocline is a valuable reference for researchers and graduate students in astrophysics, heliospheric physics and geophysics, and the dynamics of fluids and plasmas.