Research Note

First NACO observations of the Brown Dwarf LHS 2397aB^*

¹ Max-Plank Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
² European Southern Observatory, 85748 Garching bei München, Germany
³ Laboratoire d'Astrophysique, Observatoire de Grenoble, 414 rue de la Piscine, BP 53, 38041 Grenoble Cedex 9, France
⁴ Observatoire Paris-Meudon, LESIA, place Jules Janssen, 92195 Meudon Cedex, France

Corresponding author: E. Masciadri, masciadri@mpia.de

Received: 27 March 2003
Accepted: 19 August 2003

Abstract

Observations of the standard late type M8 star LHS 2397aA were obtained at the ESO-VLT 8 m telescope “Yepun” using the NAOS/CONICA Adaptive Optics facility. The observations were taken during the NACO commissioning, and the infrared standard star LHS 2397aA was observed in the H, and Ks broad band filters. In both bands the brown dwarf companion LHS 2397aB was detected. Using a program recently developed (Bouy et al. [CITE]) for the detection of stellar binaries we calculated the principal astrometric parameters (angular binary separation and position angle PA) and the photometry of LHS 2397aA and LHS 2397aB. Our study largely confirms previous results obtained with the AO-Hokupa'a facility at Gemini-North (Freed et al. [CITE]); however a few discrepancies are observed.