Deep imaging survey of the environment of α Centauri^*

II. CCD imaging with the NTT-SUSI2 camera

¹ LESIA, UMR 8109, Observatoire de Paris-Meudon, 5 place Jules Janssen, 92195 Meudon Cedex, France e-mail: Pierre.Kervella@obspm.fr
² Laboratoire Cassiopée, Observatoire de la Côte d'Azur, BP 4229, 06304 Nice Cedex 4, France

Received: 22 September 2006
Accepted: 12 November 2006

Abstract

Context.Thanks to its proximity, α Centauri is an outstanding target for an imaging search for extrasolar planets.

Aims.We searched for faint comoving companions to α Cen located at angular distances of a few tens of arcseconds, up to 2-3 arcmin.

Methods.We obtained CCD images from the NTT-SUSI2 instrument in the Bessel V, R, I, and Z bands, and archive data from 2MASS.

Results.We present a catalogue of the detected objects inside a 5.5 arcmin box around this star. A total of 4313 sources down to and were detected in the SUSI2 images. The infrared photometry of part of these sources has been extracted from the 2MASS images.

Conclusions.No comoving companion to α Centauri were detected between 100 and 300 AU, down to a maximum mass of ≈15 times Jupiter. We also mostly exclude the presence of a companion more massive than 30 M_J between 50 and 100 AU.