New variable stars in open clusters. I. Methods and results for 20 open clusters

PAUNZEN, E.; ZWINTS, K.; MAITZEN, M.H.; PINTADO, O.I.; RODE-PAUNZEN, M.

ASTRONOMY AND ASTROPHYSICS

EDPS

Año: 2004 vol. 48 p. 99 - 1023

0004-6361

We present high precision CCD photometry of 1791 objects in 20 open clusters with an age of 10 Myr to 1 Gyr. These observations were performed within the ¦¤ a photometric system which is primarily used to detect chemically peculiar stars of the upper main sequence. Time bases range from 30 min up to 60 days with data from several nights. We describe the time series analysis reaching a detection limit of down to 0.006 mag for apparent variability. In total, we have detected 35 variable objects of which four are not members of their corresponding clusters. The variables cover the entire Hertzsprung-Russell diagram, hence they are interesting targets for follow-up observations. Based on observations obtained at Complejo Astron¨®mico el Leoncito (CASLEO), operated under the agreement between the Consejo Nacional de Investigaciones Cient¨ªficas y T¨¦cnicas de la Rep¨²blica Argentina and the National Universities of La Plata, C¨®rdoba y San Juan; ESO-La Silla and UTSO-Las Campanas