Exoplanet Imager SPHERE Shipped to Chile

SPHERE — the Spectro-Polarimetric High-contrast Exoplanet REsearch instrument — is a powerful new facility for finding and studying exoplanets. The instrument has recently successfully completed testing in France, been formally accepted by ESO, and has now been shipped to Chile. It will then be installed on ESO’s Very Large Telescope (VLT) and first light is foreseen for May 2014.

SPHERE was built by a consortium of astronomers and engineers in many ESO states in conjunction with industry [1]. The consortium is led by the Institut de Planétologie et d’Astrophysique de Grenoble, France.

SPHERE’s main goal is to find and characterise giant exoplanets orbiting nearby stars by direct imaging [2]. This is an extremely challenging task as such planets are both very close to their parent stars in the sky and also very much fainter. In a normal image, even in the best conditions, the light from the star totally swamps the weak glow from the planet. The whole design of SPHERE is therefore focussed on reaching the highest contrast possible in a tiny patch of sky around the central star.

The SPHERE instrument uses several methods to achieve this and to make exoplanets visible. The first is the use of adaptive optics to correct for the effects of the Earth’s atmosphere so that images are sharper and the contrast of the exoplanet increased. Secondly a coronagraph is used to block out the light from the central star and increase the contrast still further. Finally, the light from a planet is expected to be polarised, or to have certain characteristic features in its spectrum due to molecules, while the central star will not — and this subtle difference can also be exploited to make the currently invisible visible (ann13069, eso0503).

Once SPHERE reaches Chile it will be installed on Unit Telescope 3 of the VLT and testing and commissioning will begin. The instrument is expected to see first light in May 2014 and be offered for use by the eagerly awaiting community of astronomers in late 2014.

Notes

[1] The consortium includes several European institutes, namely: Institut de Planétologie et d’Astrophysique de Grenoble, France, Max-Planck-Institut für Astronomie in Heidelberg, Laboratoire d’Astrophysique de Marseille, Laboratoire d’Etudes Spatiales et d’Instrumentation en Astrophysique de l’Observatoire de Paris, Laboratoire Lagrange in Nice, ONERA, Observatoire de Genève, Osservatorio Astronomico di Padova, Institute of Astronomy of the Zurich College of Technology, Astronomical Institute of the University of Amsterdam, ASTRON and ESO.

[2] Astronomers have already confirmed the existence of more than a thousand planets orbiting stars other than the Sun. Almost all were found using indirect methods that could detect the effects of the planets on their parent stars — the dips of brightness produced when planets crossed in front of them (the transit method), or the wobbling caused by the gravitational pull of planets in their orbits (the radial velocity method). There are only a few direct detections at present.