Gemini spectroscopy of the outer disk star cluster BH176

 

Autores
Sharina, M. E.; Donzelli, Carlos Jose; Davoust, E.; Shimansky, V. V.; Charbonnel, C.
Tipo de recurso
artículo
Estado
Versión publicada
Año de publicación
2014
País
Argentina
Institución
Consejo Nacional de Investigaciones Científicas y Técnicas
Repositorio
CONICET Digital (CONICET)
Descripción
Context: BH176 is an old metal-rich star cluster. It is spatially and kinematically consistent with belonging to the Monoceros Ring. It is larger in size and more distant from the Galactic plane than typical open clusters, and it does not belong to the Galactic bulge. Aims: Our aim is to determine the origin of this unique object by accurately determining its distance, metallicity, and age. The best way to reach this goal is to combine spectroscopic and photometric methods. Methods: We present medium-resolution observations of red clump and red giant branch stars in BH176 obtained with the Gemini South Multi-Object Spectrograph. We derive radial velocities, metallicities, effective temperatures, and surface gravities of the observed stars and use these parameters to distinguish member stars from field objects. Results: We determine the following parameters for BH176: Vh = 0 ± 15 km s-1, [Fe/H] = −0.1 ± 0.1, age 7 ± 0.5 Gyr, E(V − I) = 0.79 ± 0.03, distance 15.2 ± 0.2 kpc, α-element abundance [α/Fe] ~ 0.25 dex (the mean of [Mg/Fe], and [Ca/Fe]). Conclusions: BH176 is a member of old Galactic open clusters that presumably belong to the thick disk. It may have originated as a massive star cluster after the encounter of the forming thin disk with a high-velocity gas cloud or as a satellite dwarf galaxy.
Idioma
inglés
OAI Identifier
oai:ri.conicet.gov.ar:11336/32376
Enlace del recurso
http://hdl.handle.net/11336/32376
Nivel de acceso
Acceso abierto
Materia
Cumulos
Globulares
Galaxia
Fotometria
Astronomía
Ciencias Físicas
CIENCIAS NATURALES Y EXACTAS