NARVAL@TBL:
the first observatory dedicated to stellar magnetism
NARVAL has just been installed on
Télescope Bernard Lyot[1] atop Pic du Midi.
Like ESPaDOnS, its twin brother mounted on
Canada-France-Hawaii Telescope[2],
it is a stellar spectropolarimeter, ie an astronomical facility constructed and optimised
for studies of stellar magnetic fields and their effects on the life of stars and
their surrounding planets.
Thanks to NARVAL, the Télescope Bernard Lyot becomes the
first observatory worldwide
dedicated to these studies. And since the Sun sets in Hawaii when it rises on the
Pyrenees, NARVAL and ESPaDOnS, when working together, can continuously stare at
magnetic stars to discover the secrets of their lives!
 | ||
A new observing night starts at
Télescope Bernard Lyot
atop Pic du Midi, on which NARVAL, the ESPaDOnS twin spectropolarimeter,
was just installed.
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| A complex network of magnetic field lines is emerging from the surface of the baby star SU Aurigae. This image was obtained thanks to the combined effort of NARVAL and ESPaDOnS. Click on the image to animate the star. (© JF Donati, MM Jardine). |
"Magnetic fields are essential ingredients in the life of stars. They are both
tracers of their history, and actors of their evolution" explains Pascal Petit,
young astronomer at the Laboratoire d'Astrophysique de Toulouse-Tarbes
(CNRS, Université Paul Sabatier, Observatoire Midi-Pyrénées) and NARVAL project scientist.
"For instance, we think that the magnetic field of the Sun could be the
cause of the Little Ice Age, a period of several decades in the mid 17th century
during which winters were unusually cold over Europe. Even more spectacular is
the way magnetic fields manage to influence how stars are born,
by modifying the amount of material from which they form. However, we still know
very little about these stellar magnetic fields - even the field of the Sun is still
a mistery to us!" says Pascal Petit.
"Thanks to NARVAL, we now have an instrument and a telescope dedicated to the
study of stellar magnetic fields" says Michel Aurière, astronomer at the
Laboratoire d'Astrophysique de Toulouse-Tarbes and NARVAL project manager.
"ESPaDOnS is only available a small fraction of the time, sharing nights at
Canada-France-Hawaii Telescope with other highly popular instruments.
The advent of NARVAL, the ESPaDOnS twin, allows to overcome this limitation and
gives astronomers the possibility of
carrying out much more ambitious projets than before."
"Scientists from many different countries had perfectly understood this issue,
and massively joined from the very moment NARVAL was opened to the community",
tells David Mouillet, former director of TBL.
To demonstrate the power and complementarity of NARVAL, SU Aurigae, a baby star
located at about 450 light-years from the Sun, was looked at continuously with
both NARVAL and ESPaDOnS[3].
"With an age of only a few million years, SU Aurigae is about 1000 times younger than the
Sun" explains Jean-François Donati,
directeur de recherche at CNRS and inventor of ESPaDOnS and NARVAL.
"At this age, a star is not yet completely formed and continues to attract surrounding
material. Once captive in the magnetic web of the star, the material is redirected towards
the surface of the star along magnetic field lines like beads on a wire.
These observations tell us
that
the magnetic web of SU Aurigae is much more complex that previously
guessed through theoretical models of stellar formation, says
Jean-François Donati.
The NARVAL[4] project was carried out by the technical teams of
the Télescope Bernard Lyot and the Laboratoire d'Astrophysique de Toulouse-Tarbes;
it benefitted from the unique worldwide scientific and technical expertise that
the Toulouse team accumulated in this field of research during the last decade.
Integrated in Tarbes, NARVAL was then installed and successfully tested at Pic
du Midi in fall 2006, then
offered to the international scientific community in 2006
December.
The cost of NARVAL, about 1 M€, was funded by the
Région Midi-Pyrénées and the Ministère de la Recherche (in the framework of a
Contrat de Plan Etat-Région), the conseil Général des Hautes Pyrénées, the
European Union (FEDER funds) and the CNRS
Institut National des Sciences de l'Univers (INSU).
Contacts:
Jean-François
Donati, inventor of NARVAL/ESPaDOnS, tel: (33) 561332917 Michel Aurière, NARVAL project manager, tel: (33) 562566019
Pascal Petit, NARVAL project scientist, tel: (33) 561332828
Rémi Cabanac, TBL director, tel: (33) 562566038
Links:
CNRS/INSU press release (in french)
NARVAL webpage
ESPaDOnS webpage
TBL wepage (in french)
Pic du Midi webpage (in french)
Jean-François
Donati, inventor of NARVAL/ESPaDOnS, tel: (33) 561332917 Michel Aurière, NARVAL project manager, tel: (33) 562566019 Pascal Petit, NARVAL project scientist, tel: (33) 561332828 Rémi Cabanac, TBL director, tel: (33) 562566038 CNRS/INSU press release (in french) NARVAL webpage ESPaDOnS webpage TBL wepage (in french) Pic du Midi webpage (in french)