2006/10/20 by Giovanni Carraro, André Moitinho, Andre' Moitinho +4 · 18 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Disc #Galaxy #Metallicity #Open cluster #Photometry (optics) #Population #Spiral galaxy #Stellar population #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/510331
published in The Astronomical Journal 133(3), 1058-1066 (Institute of Physics) · 19 pages, 7 eps figures (some degraded), accepted for publication in the Astronomical Journal
arxiv created 2006/10/20 · openalex publication_date 2007/02/07 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
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 Auner1 and determine it to be 3.25 Gyr old and to lie at 8.9 kpc from the Sun. In the background of the cluster, at more than 9 kpc, we detect a young population most probably associated to the Norma Cygnus spiral arm. Furthermore, we detect the signature of an older population and identify its Turn Off and Red Giant Branch. This population is found to have a mean age of 7 Gyrs and a mean metallicity of Z = 0.006 . We reconstruct the geometry of the stellar distribution and argue that this older population - often associated to the Canis Major \it galaxy- belongs in fact to the warped old thin/thick disk component along this line of sight.