Volume 374, Number 1, July IV 2001
|Page(s)||250 - 258|
|Section||Interstellar and circumstellar matter|
|Published online||15 July 2001|
Pre-main sequence dynamos and relic magnetic fields of solar-type stars
Institute for Solar-Terrestrial Physics, PO Box 4026, Irkutsk 664033, Russia
2 School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, Scotland e-mail: email@example.com; firstname.lastname@example.org
Corresponding author: L. L. Kitchatinov, email@example.com
Accepted: 19 May 2001
We argue that contemporary magnetic fields in the radiative cores of solar-type stars are relics of hydromagnetic dynamos operating over the pre-main sequence epoch when the core formed. Simulations of differential rotation and dynamos of a 1 star are performed for a sequence of evolutionary stages of the core-growth epoch. A big difference in the dynamo-generated field between the initial and final stages of the core formation is predicted. An axisymmetric and cyclic field similar to the present day Sun is excited in a star with a mature radiative zone. An infant Sun with its core just starting to grow generates a nonaxisymmetric global field which is steady in a rotating frame. A qualitative explanation for the nonaxisymmetry is suggested. A model for the field capturing by the growing core is designed. The internal field is most efficiently captured over the initial phase when the core grows most rapidly. A nonaxisymmetric global relic field with an amplitude somewhat below 1 G is predicted for a main-sequence star of solar mass. An interpretation of the active longitude phenomenon as observed on the Sun and stars in terms of the nonaxisymmetric relic field is suggested.
Key words: stars: magnetic fields / stars: rotation / stars: interiors / stars: evolution / Sun: magnetic fields / MHD
© ESO, 2001
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.