Integrated spectral properties of 7 galactic open clusters ^*

¹ Observatorio Astronómico, Universidad Nacional de Córdoba, Laprida 854, 5000 Córdoba, Argentina
² Instituto de Física, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, 9500, Caixa Postal 15051, CEP 91501-970, Porto Alegre RS, Brazil
³ Universidad de Concepción, Departamento de Física, Casilla 160-C, Concepción, Chile

Send offprint request to: A.V. Ahumada

Received: 23 June 1999
Accepted: 21 September 1999

Abstract


This paper presents flux-calibrated integrated spectra in the range 3600-9000 Å for 7 concentrated, relatively populous Galactic open clusters. We perform simultaneous estimates of age and foreground interstellar reddening by comparing the continuum distribution and line strengths of the cluster spectra with those of template cluster spectra with known parameters. For five clusters these two parameters have been determined for the first time (Ruprecht 144, BH 132, Pismis 21, Lyngå 11 and BH 217), while the results here derived for the remaining two clusters (Hogg 15 and Melotte  105) show very good agreement with previous studies based mainly on colour-magnitude diagrams. We also provide metallicity estimates for six clusters from the equivalent widths of CaII triplet and TiO features. The present cluster sample improves the age resolution around solar metal content in the cluster spectral library for population synthesis. We compare the properties of the present sample with those of clusters in similar directions. Hogg 15 and Pismis 21 are among the most reddened clusters in sectors centered at and , respectively. Besides, the present results would favour an important dissolution rate of star clusters in these zones.