Photometry of a galactic field at l = 232°. b = -6°: The old open cluster Auner 1, The Norma-Cygnus spiral arm, and the signature of the warped galactic thick disk
We perform a detailed photometric study of the stellar populations in a Galactic field at l = 232°, b = -6° in the Canis Major (CMa) constellation. We present the first U, B, V, I photometry of the old open cluster Auner 1 and determine it to be ≈3.25 Gyr old and to lie 8.9 kpc from the Sun. In the...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2007 |
| País: | Argentina |
| Institución: | Universidad Nacional de La Plata |
| Repositorio: | SEDICI (UNLP) |
| Idioma: | inglés |
| OAI Identifier: | oai:sedici.unlp.edu.ar:10915/83126 |
| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/83126 |
| Access Level: | acceso abierto |
| Palabra clave: | Ciencias Astronómicas Galaxy: general Hertzsprung-Russell diagram Open clusters and associations: general Open clusters and associations: individual (Auner 1) |
| Sumario: | We perform a detailed photometric study of the stellar populations in a Galactic field at l = 232°, b = -6° in the Canis Major (CMa) constellation. We present the first U, B, V, I photometry of the old open cluster Auner 1 and determine it to be ≈3.25 Gyr old and to lie 8.9 kpc from the Sun. In the background of the cluster, at more than 9 kpc, we detect a young population most likely associated with the Norma-Cygnus spiral arm. Furthermore, we detect the signature of an older population and identify its turnoff and red giant branch. This population is found to have a mean age of 7 Gyr and a mean metallicity of Z = 0.006. We reconstruct the geometry of the stellar distribution and argue that this older population, often associated with the CMa "galaxy," in fact belongs to the warped old thin- and thick-disk components along this line of sight. |
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