Ruprecht 3 : an old star cluster remnant?

2MASS J and H photometry and integrated spectroscopy are employed to study the nature of the poorly populated compact concentration of stars Ruprecht 3, which was previously catalogued as an open cluster. The integrated spectrum remarkably resembles that of a moderately metal-rich globular cluster....

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Detalles Bibliográficos
Autores: Pavani, Daniela Borges, Bica, Eduardo Luiz Damiani, Ahumada, Andrea Veronica, Claria Olmedo, Juan Jose
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2003
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:10183/109129
Acceso en línea:http://hdl.handle.net/10183/109129
Access Level:acceso abierto
Palabra clave:Fotometria estelar
Espectros estelares
Galaxy: open clusters and stellar associations: general
Open clusters and associations: individual: Ruprecht 3
Methods: observational
Techniques: spectroscopic
Descripción
Sumario:2MASS J and H photometry and integrated spectroscopy are employed to study the nature of the poorly populated compact concentration of stars Ruprecht 3, which was previously catalogued as an open cluster. The integrated spectrum remarkably resembles that of a moderately metal-rich globular cluster. The distribution of the object stars in the colour-magnitude diagram is compatible with that of a 1.5 ± 0.5 Gyr open cluster or older, depending on whether the bluer stars are interpreted as turnoff stars or blue stragglers, respectively. We derive for the object a distance from the Sun dʘ = 0.72+0.04 −0.03 kpc and a colour excess E(B−V) = 0.04. Although a globular cluster remnant cannot be ruled out, the integrated spectrum resemblance to that of a globular cluster probably reflects a stochastic effect owing to the few brighter stars. The structural and photometric properties of Ruprecht 3 are compatible with what would be expected for an intermediate-age open cluster remnant.