Revealing the parameters of the open cluster Ruprecht 58

GIORGI, E.E.; VÁZQUEZ, R. A.; SOLIVELLA, G. R.; ORELLANA, R. B.; NUÑEZ, J.

New Astronomy

Año: 2007 p. 461 - 470

We present results of a study that combines UBVI photometry, MK spectral classification and proper motions in the area of the, up tonow unknown, open cluster Ruprecht 58 at the Puppis region. Star counts from the 2MASS data catalog together with the analysis ofCCD UBVI photometry demonstrate that it is a real open cluster with 90 size approximately. The cluster is placed at a distance of 3.9 kpcand is about 250 Myr old with mean reddening E(B-V)= 0.33 mag. Proper motions confirm Ruprecht 58 is a real cluster with mean absoluteproper motions lacosd = 2.77 ± 0.45 mas/yr and ld = 4.54 ± 0.45 mas/yr in the magnitude range 13.5 < V < 14.5 andlacosd = 2.70 ± 0.32 mas/yr and ld = 3.19 ± 0.32 mas/yr in the range 14.5 < V < 16.0. The computation of the cluster mass spectrumslope yielded x = 1.8 in the mass range from 1.4 to 4 M0.