Issue |
A&A
Volume 420, Number 1, June II 2004
|
|
---|---|---|
Page(s) | 17 - 32 | |
Section | Astrophysical processes | |
DOI | https://doi.org/10.1051/0004-6361:20034065 | |
Published online | 14 May 2004 |
Outflows and accretion in a star-disc system with stellar magnetosphere and disc dynamo
1
Department of Astronomy & Space Physics, Uppsala University, Box 515, 751 20 Uppsala, Sweden
2
NORDITA, Blegdamsvej 17, 2100 Copenhagen Ø, Denmark
Corresponding author: B. von Rekowski, Brigitta.vonRekowski@astro.uu.se
Received:
10
July
2003
Accepted:
3
March
2004
The interaction between a protostellar magnetosphere and a surrounding
dynamo-active accretion disc is investigated using an axisymmetric
mean-field model. In all models investigated, the dynamo-generated
magnetic field in the disc arranges itself such that in the corona,
the field threading the disc
is anti-aligned with the central dipole so that no
X-point forms.
When the magnetospheric field is strong enough (stellar surface field strength
around or larger), accretion happens in a recurrent fashion
with periods of around 15 to 30 days,
which is somewhat longer than the stellar rotation period of around 10 days.
In the case of a stellar surface field strength of at least a few
,
the star is being spun up by the magnetic torque exerted on the star.
The stellar accretion rates are always reduced by the presence of a
magnetosphere which tends to divert a much larger fraction of the disc
material into the wind.
Both, a pressure-driven stellar wind and a disc wind form. In all our models
with disc dynamo, the disc wind is structured and driven by magneto-centrifugal
as well as pressure forces.
Key words: ISM: jets and outflows / accretion, accretion disks / magnetic fields / magnetohydrodynamics (MHD)
© ESO, 2004
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.