Fundamental parameters of the moderately young open clusters NGC 5999, NGC 6031, Ruprecht 115 and Ruprecht 120

We present CCD BVI Johnson–Cousins photometry for the southern open clusters NGC 5999, NGC 6031, Ruprecht 115 and Ruprecht 120. The sample consists of about 1160 stars reaching down to V ~ 19 mag. From the analysis of the colour–magnitude diagrams, we confirm the reality of the clusters and derive t...

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Detalles Bibliográficos
Autores: Piatti, Andres E., Claria Olmedo, Juan Jose, Bica, Eduardo Luiz Damiani
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:1999
País:Brasil
Institución:Universidade Federal do Rio Grande do Sul (UFRGS)
Repositorio:Repositório Institucional da UFRGS
Idioma:inglés
OAI Identifier:oai:www.lume.ufrgs.br:10183/88773
Acceso en línea:http://hdl.handle.net/10183/88773
Access Level:acceso abierto
Palabra clave:Aglomerados estelares e associacoes
Composicao estelar
Evolucao estelar
Fotometria estelar
Espectros estelares
Methods: observational
Open clusters and associations: general
open clusters and associations: individual: NGC 5999
Open clusters and associations: individual: NGC 6031
Open clusters and associations: individual: Ruprecht 115
Open clusters and associations: individual: Ruprecht 120.
Descripción
Sumario:We present CCD BVI Johnson–Cousins photometry for the southern open clusters NGC 5999, NGC 6031, Ruprecht 115 and Ruprecht 120. The sample consists of about 1160 stars reaching down to V ~ 19 mag. From the analysis of the colour–magnitude diagrams, we confirm the reality of the clusters and derive their fundamental parameters (reddening, distance and age). We also present integrated spectra for NGC 6031, Ruprecht 115 and Ruprecht 120, covering a range from 3500 to 9200 Å. From the equivalent widths of Balmer and infrared Ca II triplet lines, as well as from a comparison of the obtained spectra with those of template clusters, we derive reddening, age and metallicity. The photometric and spectroscopic results allow us to conclude that the four clusters are moderately young (age ~ 100–500 Myr) and are located approximately towards the Galactic Centre at ~ 2.3 kpc from the Sun. NGC 6031 and Ruprecht 120 have nearly solar metal content, while Ruprecht 115 appears to be slightly metal-rich.