The Calar Alto lunar occultation program: update and new results

¹ European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching bei München, Germany e-mail: arichich@eso.org
² Departament d'Astronomia i Meteorologia, Universitat de Barcelona, Martí i Franqués 1, 08028 Barcelona, Spain
³ Observatori Fabra, Camí de l'Observatori s/n, 08035 Barcelona, Spain
⁴ Computer Vision Center, UAB, Bellaterra, Spain
⁵ Escola Universitaria Politècnica de Barcelona, Universitat Politècnica de Catalunya, Barcelona, Spain
⁶ Calar Alto Observatory, Almería, Spain
⁷ Universidad de Jaén, Dpto. de Física, Campus Las Lagunillas s/n, 23071, Jaén, Spain
⁸ Real Instituto y Observatorio de la Armada, San Fernando, Spain

Received: 25 July 2005
Accepted: 12 September 2005

Abstract

We present an update of the lunar occultation program which is routinely carried out in the near-IR at the Calar Alto Observatory. A total of 350 events were recorded since our last report (Fors et al. 2004, A&A, 419, 285). In the course of eight runs we have observed, among others, late-type giants, T-Tauri stars, and infrared sources. Noteworthy was a passage of the Moon close to the galactic center, which produced a large number of events during just a few hours in July 2004. Results include the determinations of the angular diameter of RZ Ari, and the projected separations and brightness ratios for one triple and 13 binary stars, almost all of which representing first time detections. Projected separations range from to . We provide a quantitative analysis of the performance achieved in our observations in terms of angular resolution and sensitivity, which reach about and mag, respectively. We also present a statistical discussion of our sample, and in particular of the frequency of detection of binaries among field stars.