Ruprecht 1: a moderately young open cluster with nearly solar metallicity in the third galactic quadrant

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

Garching

Conferencia; The MPA/ESO/MPE/USM 2008 Joint Astronomy Conference: Chemical Evolution of Dwarf Galaxies and Stellar Clusters; 2008

MPA/ESO/MPE/USM (Alemania)

New CCD observations with the C and T1 filters of the Washington system for 862 stars in the field of the open cluster Ruprecht1 are presented. The cluster turned out to be very small, its linear radius being 2.6±0.2pc. Our analysis demonstrates that Ruprecht1 is moderately reddened [E(B-V)=0.25] and moderately young (approx. 230Myr). Heliocentric distances of 1.9±0.4kpc and 1.5±0.3kpc are determined for Z(metallicity) = 0.02 and 0.08, respectively, although evidence is presented favoring a solar metal content rather than a subsolar one. We compare the cluster properties with those of known open clusters located within 1kpc around it. We confirm that the greater the height out of the Galactic plane, the lower the interstellar visual absorption. Ruprecht1 is about as old as the average age of the selected clusters in that volume (2008,Baltic Astron.,17,67).