Reddening and age for 13 southern Galactic open clusters determined from integrated spectra^*

¹ Observatorio Astronómico, Universidad Nacional de Córdoba, Laprida 854, 5000 Córdoba, Argentina e-mail: andrea@mail.oac.uncor.edu, mctorres@mail.oac.uncor.edu
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 e-mail: bica@if.ufrgs.br
³ Instituto Astronomico e Geofisico da USP, CP 3386, São Paulo 01060-970, Brazil e-mail: dutra@andromeda.iagusp.usp.br

Corresponding author: J. J. Clariá, claria@mail.oac.uncor.edu

Received: 6 July 2001
Accepted: 13 August 2001

Abstract

In this study we present flux-calibrated integrated spectra in the range 3800-6800 Å for 13 concentrated open clusters with Galactic longitudes between 219° and 316°, nine of which have not been previously studied. Using the equivalent widths of the Balmer lines and comparing the cluster spectra with template spectra of Magellanic Clouds and Galactic star clusters with known parameters, we derive both foreground interstellar reddening values and age. For nine clusters these two parameters have been determined for the first time, while for the rest of the sample the results show good agreement with previous studies. The present analysis indicates four very young (Hogg 11, NGC 5606, vdB-RN 80 and Pismis 17), seven moderately young (ESO 429-SC13, Hogg 3, Hogg 12, Haffner 7, BH 87, NGC 2368 and Bochum 12) and two intermediate-age (Berkeley 75 and NGC 2635) open clusters. The derived foreground interstellar reddening values are in the range . The age and reddening distributions of the present sample of relatively faint open clusters match those of open clusters with known parameters in a 90° sector centered at .