Adaptive optics imaging survey of the Tucana-Horologium association

¹ Laboratoire d'Astrophysique, Observatoire de Grenoble, 414 rue de la piscine, 38041 Saint-Martin d'Hères, France
² Imperial College of Science, Technology and Medecine, Exhibition Road, London SW7 2AZ, UK
³ Jet Propulsion Laboratory, Mail Stop 183-501, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
⁴ Office National Études et de Recherches Aérospatiales, Département d'optique théorique et appliquée, BP 72, 29 avenue de la Division Leclerc, 92322 Châtillon Cedex, France
⁵ Department of Physics and Astronomy, University of California, Los Angeles, 8371 Math Science Building, Box 951562, CA 90095-1562, USA
⁶ Laboratoire d'Astrophysique, Observatoire Midi-Pyrénénes, BP 826, 65008 Tarbes, France

Corresponding author: G. Chauvin, gchauvin@obs.ujf-grenoble.fr

Received: 29 July 2002
Accepted: 4 March 2003

Abstract

We present the results of an adaptive optics (AO) imaging survey of the common associations of Tucana and Horologium, carried out at the ESO 3.6 m telescope with the ADONIS/SHARPII system. Based on our observations of two dozen probable association members, HIP 1910 and HIP 108422 appear to have low-mass stellar companions, while HIP 6856 and GSC 8047-0232 have possible sub-stellar candidate companions. Astrometric measurements, performed in November 2000 and October 2001, indicate that HIP 1910 B likely is bound to its primary, but are inconclusive in the case of the candidate companion to HIP 6856. Additional observations are needed to confirm the HIP 6856 companionship as well as for HIP 108422 and GSC 8047-0232.