Based on observations collected at Observatório do Pico dos Dias (OPD), operated by the Laboratório Nacional de Astrofísica, CNPq, Brazil.

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Table 2 is only available in electronic form at http://www.aanda.org

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... Lyra

Present address: Department of Physics and Astronomy, Uppsala Astronomical Observatory, Box 515, 751 20 Uppsala, Sweden.

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... Keller

Present address: Universidade de São Paulo, Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Depto. de Astronomia, Rua do Matão 1226, CEP: 05508-900, São Paulo, SP, Brazil.

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...

Image Reduction and Analysis Facility (IRAF) is distributed by the National Optical Astronomical Observatories (NOAO), which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under contract to the National Science Foundation (NSF).

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