First estimates of the fundamental parameters of the very small open cluster Ruprecht 1

PIATTI, A. E.; CLARIÁ, J. J.; PARISI, M. C.; AHUMADA, A. V.

San Juan - Argentina

Congreso; 51 Reunión de la Asociación Argentina de Astronomía; 2008

New CCD observations with the Washington C and T1 filters in the field of the open cluster Ruprecht 1 are presented. The cluster turned out to be very small, its linear radius being 2.6 +/- 0.2 pc. Ruprecht 1 is moderately reddened [E(B-V) = 0.25] and moderately young (~ 230 Myr). Heliocentric distances of 1.9 +/- 0.4 kpc and 1.5 +/- 0.3 kpc are determined for Z (metallicity) = 0.02 and 0.08, respectively, although evidence is presented favouring a solar metal content rather than a subsolar one. We compare the cluster properties with tose of known open clusters located within 1 kpc around it.