Spectroscopic determination of fundamental parameters of small angular diameter galactic open clusters

A.V. AHUMADA, J. J. CLARIÁ, E. BICA, M. C. PARISI, M. C. TORRES Y D.B. PAVANI

Capilla del Monte, Córdoba

Congreso; 49º Reunión Anual de la Asociación Argentina de Astronomía; 2006

Observatorio Astronómico de la Univ. Nac. de Córdoba

We present integrated spectra obtained at CASLEO (Argentina)for 9 galactic open clusters of small angular diameter. Two of them(BH 55 and Rup 159) have not been the target of previous research. The flux-calibrated spectra cover the spectral range  ~3600-6900 A. Using the equivalent widths (EWs) of the Balmer lines and comparing the cluster spectra with template spectra, we determined E(B-V) colour excesses andages for the present cluster sample. The parameters obtained for 6 of theclusters show good agreement with previous determinations based mainlyon photometric methods. This is not the case, however, for BH90, a scarcelyreddened cluster, for which Moffat & Vogt (1975b) derived E(B-V)= 0.51. We explain and justify the strong discrepancy found for this object.According to the present analysis, 3 clusters are very young (Bo 14,Tr 15 and Tr 27), 2 are moderately young (NGC 6268 and BH205), 3are Hyades-like clusters (Rup 164, BH90 and BH55) and only one is anintermediate-age cluster (Rup 159).