Home Newsletter
News Books
Welcome to FreeScience.info Language/Lingua

Books 3054
· Book News
· Most clicked
· Least clicked

Search for a Book
Add a new Book

Magnetic fields in massive stars, their winds, and their nebulae

Author: Rolf Walder, Doris Folini, Georges Meynet
Url: http://arxiv.org/abs/1103.3777
Format: Ps, Pdf
Year: 2011
Category: Astrophysics of stars
Pages: 44
Clicks: 590

Massive stars are crucial building blocks of galaxies and the universe, as production sites of heavy elements and as stirring agents and energy providers through stellar winds and supernovae. The field of magnetic massive stars has seen tremendous progress in recent years. Different perspectives -- ranging from direct field measurements over dynamo theory and stellar evolution to colliding winds and the stellar environment -- fruitfully combine into a most interesting and still evolving overall picture, which we attempt to review here. Zeeman signatures leave no doubt that at least some O- and early B-type stars have a surface magnetic field. Indirect evidence, especially non-thermal radio emission from colliding winds, suggests many more. The emerging picture for massive stars shows similarities with results from intermediate mass stars, for which much more data are available. Observations are often compatible with a dipole or low order multi-pole field of about 1 kG (O-stars) or 300 G to 30 kG (Ap / Bp stars). Weak and unordered fields have been detected in the O-star zeta-Ori A and in Vega, the first normal A-type star with a magnetic field. Theory offers essentially two explanations for the origin of the observed surface fields: fossil fields, particularly for strong and ordered fields, or different dynamo mechanisms, preferentially for less ordered fields. Numerical simulations yield the first concrete stable (fossil) field configuration, but give contradictory results as to whether dynamo action in the radiative envelope of massive main sequence stars is possible. Internal magnetic fields, which may not even show up at the stellar surface, affect stellar evolution as they lead to a more uniform rotation, with more slowly rotating cores and faster surface rotation. Surface metallicities may become enhanced, thus affecting the mass-loss rates.

Similar Books
Struttura ed evoluzione delle stelle
The Life of a Star
The Fundamentals of Stellar Astrophysics
The Virial Theorem in Stellar Astrophysics
Fondamenti di Astrofisica Stellare
Stellar Atmospheres
The magnetic fields of forming solar-like stars
Massive Stars and their Supernovae
The solar magnetic field
Advances in Global and Local Helioseismology: an Introductory Review
The physics of neutron stars
Relativistic Binaries in Globular Clusters
Recent Advances in Understanding Particle Acceleration Processes in Solar Flares
The First Stars
Stellar Superfluids
Neutrinos and the stars

Home |  Authors | About | Contact Us |  Email 
 Copyright © 2002-2013 FreeScience.info. 

Best viewed with Mozilla 1.X 1024x768
free scientific books