My research involves studying different aspects of solar-type stars.
Stellar imaging: I map the surfaces of young solar-type stars using indirect imaging techniques called
Doppler imaging and Zeeman Doppler imaging. These imaging techniques
are based on the same tomograpic principles used in medicine (e.g., magnetic resonance imaging, MRI) and
geography (e.g., seismic tomography). They enable us to reconstruct surface brightness maps and magnetic
field maps of stars that are over 1500 light years away (approx. 460 parsecs or 1019 metres).
Spots on young stars:
The coronae of stars: I use X-ray data and modelling techniques to model the detailed structure
of stellar corone in young stars (see Hussain et al. 2007) and a recent poster from the X-ray 2009 conference in Bologna. The inspiration for much of this work comes from work on
the Sun. Solar physicists have been extrapolating solar surface magnetograms to model coronal properties of the Sun as observed in missions such as
My work exploits these methods in order to learn why the coronae of young stars are over 100 times more
hot and active (with massive flares) than our own relatively sedate Sun.
Are they scaled up versions of the Sun or do they have fundamentally
different heating mechanisms?
Ultimately we hope to understand how
they interact with and affect the formation and evolution
of their surrounding planets.
Rotation in very young stars:
We know very little about magnetic fields in very young stars (1-10 Myr old stars called T Tauri stars),
yet they are of key importance when explaining the
fundamental properties of young stars.
For instance, the rotational evolution of young stars is explained by the
interaction of T Tauri coronal magnetic fields with their surrounding disks.
However, there are relatively few measurements of rotation rates for stars that are very highly variable
at X-ray wavelengths. I am using VLT data to conduct a survey of rotational velocities and to classify the spectral types of
X-ray active stars
in the Orion Nebula Cluster in order to test theoretical predictions about the effect that the stellar temperature (and therefore
its structure) and its rotation rate has on the intense observed X-ray activity from these stars.