REDDENING AND AGE OF 15 SOUTHERN GALACTIC OPEN CLUSTERS DETERMINED FROM INTEGRATED SPECTROSCOPY

A.V. AHUMADA; J.J. CLARIÁ; E. BICA; M.C. PARISI; D.B. PAVANI

Isla Margarita - Venezuela

Congreso; XII IAU Regional Latin American Meeting of Astronomy; 2007

We present flux-calibrated integrated spectra obtained at CASLEO (Argentina) in the range 3800-6800 A for 15 small angular diameter Galactic open clusters. Using the equivalent widths of the Balmer lines and comparing the cluster spectra with solarmetallicity template spectra of Galactic star clusters with known properties, we derive both foreground E(B-V) colour excesses and ages. Five out of the 15 studied clusters had not been the subject of previous studies so that the fundamental parameters determined in the current work turn out to be the first of their kind. For the remaining clusters, we provide independent information of that derived from colour-magnitude diagram studies. Five clusters are found to be very young (BH121, H205, Bochum14, Tr 15 and Tr 27), four are moderately young (Collinder 258, BH92, Pismis 23 and NGC6268), three are Hyades-like age clusters (Ruprecht 158, BH55 and BH90), one is an intermediate-age cluster  Ruprecht 164) and two are definitely old (ESO65-SC7 and Ruprecht 159). The E(B-V) colour excesses derived for the whole sample range from ~ 0.0 in Ruprecht 158 to ~ 2.40 in Tr 27,  while the ages vary from ~3 Myr to ~2 Gyr. The age and reddening distributions of the present cluster sample match those of open clusters with known parameters in a 110° sector centered at l = 310°.