Magnetic activity in late-type giant stars: Numerical MHD simulations of non-linear dynamo action in Betelgeuse

Evidence is presented from numerical magneto-hydrodynamical simulations for the existence of magnetic activity in late-type giant stars. A red supergiant with stellar parameters similar to that of Betelgeuse (α Orionis) is modeled as a “star-in-a-box” with the high-order “Pencil Code”. Both linear k...

Full description

Saved in:
Bibliographic Details
Published in:Astronomy and astrophysics (Berlin) 2004-09, Vol.423 (3), p.1101-1107
Main Author: Dorch, S. B. F.
Format: Article
Language:English
Subjects:
Astrophysics
Cosmology and Extra-Galactic Astrophysics
magnetohydrodynamic: (MHD)
Physics
Sciences of the Universe
stars: activity
stars: AGB and post-AGB
stars: individual: Betelgeuse
stars: late-type
stars: magnetic fields
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Evidence is presented from numerical magneto-hydrodynamical simulations for the existence of magnetic activity in late-type giant stars. A red supergiant with stellar parameters similar to that of Betelgeuse (α Orionis) is modeled as a “star-in-a-box” with the high-order “Pencil Code”. Both linear kinematic and non-linear saturated dynamo action are possible: the non-linear magnetic field saturates at a super-equipartition value corresponding to surface magnetic field of field strengths up to ~500 Gauss. In the linear regime two different modes of dynamo action are found with exponential growth rates of ~4 and 25 years, respectively. It is speculated that magnetic activity of late-type giants may influence dust and wind formation and possibly lead to the heating of the outer atmospheres of these stars.
ISSN:0004-6361
1432-0746
1432-0756
DOI:10.1051/0004-6361:20040435