Thanks to its very high angular resolution, AMBER enables the observation of practically all stages in the evolution of stars, from their infancy to their death. This equipment is unique in the world and was built by a consortium managed by CNRS-associated French teams with the support of the INSU/CNRS1. Astronomy and Astrophysics devotes a special issue in March 2007 to this remarkable facility.

Having recombined the beams from the different VLT telescopes, AMBER analyses the signal using a spectrograph. Working in the near infrared field at 1 to 2.5 microns, AMBER now renders the VLT the largest telescope ever available, with an equivalent mirror diameter of more than 130 metres, corresponding to a resolution 16 times better than that of a single telescope, and a collection area of more than 150m.

Use of the interferometric mode can overcome some of the problems faced by astronomers when building extremely large telescopes, and constitutes an essential complement to very large surface instrument by specialising in enhancing the resolving power. It then becomes possible to probe the formative regions of planets, to observe the winds of very rapidly rotating stars, to study the different types of matter ejected by a massive star, to separate the two components of a tight binary star and directly visualise the evolution of a nova only a few days after its explosion.

One of the results presented in Astronomy and Astrophysics concerns the eruption on February 12, 2006, of the recurrent nova, RS Oph, only 25 years after a similar eruption which was actively observed in 1985. RS Oph then became visible to the naked eye and was the subject of intense observations not only by numerous amateur astronomers but also by most of the major observatories on Earth and in space.

This extreme system was observed for the first time by optical interferometers - including AMBER on the VLTI - only 5 days after its discovery. These observations revealed a complex geometry and kinetics, far removed from the simple representation of an expanding, spherical ball of fire.

In particular, AMBER detected a high velocity jet, probably perpendicular to the orbital plan of the binary system, and enabled detailed study of the shock wave and wind generated by the nova. Another important observation by AMBER concerned the star ? Carinae, one of the most massive and luminous stars in our galaxy. It showed that ? Carinae is completely obscured by a oblong cloud of expanding gas, called a wind. Because the strength of this wind is latitude-dependent,

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Related Links
AMBER site at the LAOG
CNRS
Stellar Chemistry, The Universe And All Within It