Composed of a set of lectures and tutorial reviews, this book stems from a summer school devoted to the gravitational aspects of the sun and their geophysical consequences. Contribitions elaborate on the gravitational distortions of the sun which can be used to gain some knowledge of the sun's interior and surface phenomena but which also influences the sun's irradience and thus ultimately the earth's climate. Last but not least, it is shown that these small distortions constitute a formidable challenge to solar astrometry, and the final part of the book describes the observational difficulties in defining unequivocally the solar diameter.

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.

This book comprises an excursion through space weather, a scientific topic in rapid growth and with growing impact and implications for technological societies. The text is aimed at students and scientists working, or interested in, the field and provides a thorough introduction to the topic for those who wish to become acquainted with the basic solar physics at the origin of space weather.

The mapping of the surface of stars requires diverse skills, analysis techniques and advanced modeling, i.e. the collaboration of scientists in various specialties. This volume gives insights into new techniques allowing for the first time to obtain resolved images of stars. It takes stock of what has been achieved so far in Chile, on the ESO VLTI instrument or, in the States, on the CHARA instrument. In recent times interferometry, combined with adaptive optics has allowed to reconstruct images of stars. Besides the Sun (of course) by now five stars have been resolved in detail. In addition to interferometry, this book highlights techniques used for mapping the surfaces of stars using photometry made by space observatories; Zeeman- and Doppler Imaging; mapping the surface element abundances via spectroscopy. This book will also take stock of the best images of the solar surface, made by connecting the differential rotation to the underlying physical parameters derived from helioseismology. Recent measurements of flattening of the solar surface by SDO showed that the Sun's shape is linked to the rotation of the core. It is shown how such a result is generalizable to the stars.

Composed of a set of lectures and tutorial reviews, this book stems from a summer school devoted to the gravitational aspects of the sun and their geophysical consequences. Contribitions elaborate on the gravitational distortions of the sun which can be used to gain some knowledge of the sun's interior and surface phenomena but which also influences the sun's irradience and thus ultimately the earth's climate. Last but not least, it is shown that these small distortions constitute a formidable challenge to solar astrometry, and the final part of the book describes the observational difficulties in defining unequivocally the solar diameter.

Based on lectures given at a CNRS summer school in France, this book covers many aspects of stellar environments (both observational and theoretical) and offers a broad overview of the field. More specifically, Part I of the book focuses on the Sun, the properties of the ejected plasma, of the solar wind and on space weather. The second part deals with tides in planetary systems and in binary stellar systems, as well as with interactions in massive binary stars as seen by interferometry. Finally the chapters of Part III discuss the very close environments of young stars; Stellar Winds, Magnetic Fields and Disks; Magnetic field and convection in the cool supergiant Betelgeuse; The formation of circumstellar disks around evolved stars; and an introduction to accretion disks is given. With its broad approach the book will provide graduate students with a good overview of the environments of the Sun and stars.

This volume of lecture notes brings together the knowledge on pulsations of the Sun and the stars, with a particular emphasis on recent observations and modelling, and on the influence of pulsations of other physical processes. The book begins with an extensive introduction to helioseismology. The solar cycle and gravity modes are discussed before the focus is widened from helioseismology to asteroseismology which is detailed in a series of specific chapters. Based on courses given at a graduate school, these tutorial lecture notes will be of interest and useful to a rather broad audience of scientists and students.

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.