Although just offerered to the astronomical community (in Dec 2006, on a 'shared-risk' policy),
NARVAL has already contributed to obtain a significant scientific result. On late
November and early December 2006, NARVAL and ESPaDOnS simultaneously
observed SU Auriga,
a newly-born star weighting about twice
as much as the Sun
and located at a distance of about 450 light years from us.
With an age of only a few million years (as opposed to 5 billion years
for the Sun), SU Aur is still in its extreme infancy.
Baby stars like SU Aur are not yet completely formed and still accrete mass from
the protostellar disc that surrounds them. Magnetic field is
what connects the
star to its surrounding disc, with material flowing from the inner disc rim to
the stellar surface along field lines as beads along wires. Magnetic fields thus
impact the way stars are formed.
Existing models of stellar formation assume that the magnetic field of baby stars
is fairly simple, resembling that of a simple magnet bar or that of the Earth. The
new observations of SU Aur collected with NARVAL and ESPaDOnS suggest that
in protostars are significantly more complex than previously thought.
These data were collected in
the framework of a French/UK project aimed at studying magnetic fields of
baby stars. This project is led by JF Donati (Observatoire Midi-Pyrenees)
and involves astrophysicists from UK (M Jardine, A Cameron, T Harries, G Hussain
and Y Unruh), from Grenoble (J Bouvier, J Ferreira, C Dougados, F Ménard) and
from Toulouse (P Petit, S Jeffers, F Paletou).