2011/04/26 by I. Platais, K. M. Cudworth, V. Kozhurina-Platais +5 · 3 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Stellar, planetary, and galactic studies #astro-ph.SR
paper · pdf · doi:10.1088/2041-8205/733/1/l1
published as ApJ Letters, 733, L1, 2011 May 20 · 15 pages, 4 figures, published in ApJL
openalex publication_date 2011/04/26 · arxiv created 2011/04/28 · arxiv updated 2011/04/29 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
We present comprehensive cluster membership and g ' r ' photometry of the prototypical old, metal-rich Galactic star cluster NGC 6791. The proper-motion catalog contains 58,901 objects down to g '∼ 24, limited to a circular area of radius 30'. The highest precision of the proper motions is 0.08 mas yr −1 . Our proper motions confirm cluster membership of all main and also some rare constituents of NGC 6791. The total number of probable cluster members down to g ' = 22 ( M V ∼ +8) is ∼4800, corresponding to M tot ≈ 5000 M ☉ . New findings include an extended horizontal branch in this cluster. The angular radius of NGC 6791 is at least 15' (the effective radius is R h ≃ 4 4 while the tidal radius is r t ≃ 23'). The luminosity function of the cluster peaks at 4.5 and then steadily declines toward fainter magnitudes. Our data provide evidence that differential reddening may not be ignored in NGC 6791.