Cool Stars 14 - Submitted Abstract # 327
This version created on 05 October 2006

Coronal Structure of Pre-Main Sequence Stars


Moira Jardine, University of St. Andrews

The study of pre-main sequence stellar coronae is undertaken in many
different wavelength regimes, with apparently conflicting results.
X-ray studies of T Tauri stars suggest the presence of loops with a
range of sizes ranging from less than a stellar radius to 10  stellar
radii.  Some of these stars show a clear rotational modulation in
X-rays, but many do not and indeed the nature of this emission and its
dependence on stellar mass and rotation rate is still a matter of
debate.  Some component of it may come from the accretion shock, but
the location and extent of the accretion funnels (inferred from
optical and UV observations) is as much of a puzzle as the mass
accretion rate that they carry.  Equally central to the spin evolution
of the system is the loss of mass and angular momentum from the system
in either jets or winds.  Linking all these different features is the
magnetic field.  Recent observations suggest the presence of structure
on many scales, with a complex, multipolar field on small scales near
the surface co-exisiting with a much simpler field structure on the
larger scales at which the stellar field may be linking onto a
surrounding disk.  Some recent models suggest that the open field
lines which are responsible for carrying gas escaping in winds and
jets may also be responsible for much of the infalling accretion flow.
The aim of this splinter session is to bring together the most recent
results from these different wavelength regimes to see if a consistent
picture emerges which can shed light on the structure of the coronae
of these young objects.

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