Coronagraphic search for wide substellar companions among members of the Ursa Major moving group

Context. We present the results of a survey to detect low-mass companions of Ursa Major (UMa) group members, carried out in 2003–2006 with NACO at the ESO VLT. While many extra-solar planets and planetary candidates have been found in close orbits around stars by the radial velocity and the transit methods, direct detections at wider orbits are rare. The UMa group, a young nearby stellar association at an age of about 200–600 Myr, has not yet been addressed as a whole although its members represent a very interesting sample to search for and characterize substellar companions by direct imaging.