NGC 6939

(Melotte 231; Collinder 423; MWSC 3357; OCL 217; FSR 0315; FoF 640)

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1.0 UTI
1.0
CN
1.0
Cdens
1.0
CC3
1.0
Clit
1.0
Cdup
N50 (P>50% members) 1143
Stellar density (N50/rad) 56.1 [N/pc2]
C3 classification AA
  • CN 1.0 Very rich
  • Cdens 1.0 Very dense
  • CC3 1.0 Very high quality
  • Clit 1.0 Very well-studied
  • Cdup 1.0 Unique
πŸ“₯ Members πŸ“Š Colab πŸ”¬ Bayestar19 MOCAMOCA πŸ” CDS πŸ” Simbad πŸ” CDS (Ξ±, Ξ΄) πŸ” Simbad (Ξ±, Ξ΄)

Overview
ℹ️
NGC 6939 is a very rich, very dense object of very high C3 quality. Its parallax locates it at a relatively close distance, above the mid-plane, affected by moderate extinction. It is catalogued as a massive, near-solar metallicity, old cluster, but with a large variance across recent sources for the metallicity and mass parameters (see Parameters). It is very well-studied in the literature.

Note: This object contains blue stragglers according to at least one source.

Almeida et al. (2025)
Mass determination: good fit. Isochrone match: good fit. Gold sample.

Cavallo et al. (2024)
Gold sample.

Hunt & Reffert (2024)
Classified as open cluster. CMD class: 0.99 (50th percentile).

Ahumada & Lapasset (2007)
Membership probabilities from (1985ChA&A...9..300Z): star 7, 98%; star 13, 97%; star 87, 86%; star 94, 99%. Stars 7 and 13 (2002AJ....124.2093R), and 59 and 349 (WEBDA) are cited as straggler candidates in (1969MNRAS.144..449C) and (1994AJ....108.1828M). Star 59 is also cited as a blue straggler in (1988PASP..100..338G), although is probably a non-member.

Data
πŸ” Search references for NGC 6939 in: SciX Simbad
ℹ️
Reference Year RA [deg] DEC [deg] Plx [mas] pmRA [mas/yr] pmDE [mas/yr] Rv [km/s]
UCC 99999– 307.919 60.653 0.522 -1.82 -5.459 -19.096
Bijavara Seshashayana et al. 2025 307.721 60.61 – – – –
Li et al. 2025 307.917 60.653 0.506 -1.841 -5.413 –
Hu & Soubiran 2025 307.932 60.657 – – – –
Wei et al. 2025 307.924 60.651 0.525 -1.819 -5.454 –
Carrasco-Varela et al. 2025 307.968 60.689 – – – –
Almeida et al. 2025 307.928 60.655 – – – –
Hunt & Reffert 2024 307.901 60.651 0.525 -1.817 -5.462 -18.805
Cavallo et al. 2024 307.932 60.657 0.525 – – –
Hunt & Reffert 2023 307.901 60.651 0.525 -1.817 -5.462 -18.805
Almeida et al. 2023 307.937 60.65 – – – –
Just et al. 2023 307.879 60.657 – – – –
Jadhav & Subramaniam 2021 307.917 60.653 – – – –
Jaehnig et al. 2021 307.914 60.655 0.54 -1.845 -5.42 –
Rain et al. 2021 307.917 60.653 0.506 -1.841 -5.413 –
Dias et al. 2021 307.928 60.655 0.506 -1.838 -5.41 -18.775
Cantat-Gaudin et al. 2020 307.917 60.653 0.506 -1.841 -5.413 –
SΓ‘nchez et al. 2020 307.875 60.662 – -1.9 -5.284 –
Cantat-Gaudin & Anders 2020 307.917 60.653 0.506 -1.841 -5.413 –
Liu & Pang 2019 307.919 60.648 0.508 -1.845 -5.408 –
Soubiran et al. 2018 307.917 60.653 – – – -18.99
Bica et al. 2019 307.817 60.63 – – – –
Cantat-Gaudin et al. 2018 307.917 60.653 0.506 -1.841 -5.413 –
Loktin & Popova 2017 307.875 60.662 – -0.67 -0.41 -42.0
Kharchenko et al. 2016 307.879 60.657 – – – –
Dias et al. 2014 307.875 60.662 – -2.37 -5.29 –
Kharchenko et al. 2013 307.882 60.66 – -2.07 -1.35 -42.0
Gozha et al. 2012 307.875 60.662 – – – –
Kharchenko et al. 2012 307.882 60.66 – -2.13 -1.34 -42.0
Bukowiecki et al. 2011 307.875 60.66 – – – –
Kharchenko et al. 2007 307.87 60.66 – 0.08 – –
Ahumada & Lapasset 2007 307.875 60.667 – – – –
van den Bergh 2006 307.875 60.662 – – – –
Chen et al. 2003 307.879 60.657 – – – –
Dias et al. 2002 307.875 60.662 – -2.37 -5.29 -42.0
Lynga 1987 307.857 60.641 – – – –
Sulentic et al. 1973 307.85 60.635 – – – –

πŸ’‘ Note: The UCC values are estimated from its identified members.

Reference Year Dist [kpc] Av [mag] DAv [mag] Age [Myr] [Fe/H] [dex] Mass [Msun] Bfrac BSS
UCC 99999– 1.8 1.01 1.29 1698 0.010 2959 0.59 4
Bijavara Seshashayana et al. 2025 – 0.85 – 1700 -0.020(14) – – –
Li et al. 2025 1.73 1.29 – 1695 -0.155 – – –
Hu & Soubiran 2025 – – – – 0.050(5) – – –
Wei et al. 2025 2.24 1.11 – 1780 0.250 3101 0.59 –
Carrasco-Varela et al. 2025 1.76 0.92 – 1611 0.450 – – 5(1)
Almeida et al. 2025 1.76 0.92 – 1611 – 2306 – –
Hunt & Reffert 2024 – – – – – 5146(1) – –
Cavallo et al. 2024 1.85 1.24 – 1259 0.300 – – –
Hunt & Reffert 2023 1.84 1.33 1.29 1050 – – – –
Almeida et al. 2023 1.72 1.40 – 1524 -0.007 2031(1) 0.59 –
Just et al. 2023 – – – 1862 – 1219 – –
Spina et al. 2022 – – – – 0.105 – – –
Jadhav & Subramaniam 2021 1.82 0.85 – 1698 – 4526 – 3(1)
Jaehnig et al. 2021 1.86(1) – – – – – – –
Rain et al. 2021 1.87 1.04 – 1585 – – – 2
Dias et al. 2021 1.76 0.92 – 1611 0.462 – – –
Cantat-Gaudin et al. 2020 1.82 0.85 – 1698 – – – –
Kounkel et al. 2020 1.80 1.24 – 1738 – – – –
Cantat-Gaudin & Anders 2020 1.87 – – – – – – –
Liu & Pang 2019 – – – 1660 0.500 – – –
Soubiran et al. 2018 1.87 – – – – – – –
Cantat-Gaudin et al. 2018 1.87 – – – – – – –
Loktin & Popova 2017 1.39 0.98 – 2183 – – – –
Kharchenko et al. 2016 1.80 0.98 – 1862 – – – –
Kharchenko et al. 2013 1.80 0.98 – 1862 0.000 – – –
Bukowiecki et al. 2012 – – – – – 2959 – –
Gozha et al. 2012 1.80 – – 1585 0.000 – – –
Kharchenko et al. 2012 1.80 0.98 – 1871 0.000 – – –
Bukowiecki et al. 2011 1.60(1) 0.95 – 1413 – – – –
Ahumada & Lapasset 2007 – 1.01 – 2239 – – – 5
van den Bergh 2006 1.19 1.01 – 2239 – – – –
Chen et al. 2003 1.19 1.01 – 2210 0.020(1) – – –
Dias et al. 2002 1.80 1.04 – 1585 0.000 – – –
Lynga 1987 1.25 1.51 – 1820 -0.110 – – –

(N): Indicates that there are N extra values assigned to this parameter in the corresponding reference.

Visualization
ℹ️
NGC 6939 UCC
NGC 6939 HUNT23
NGC 6939 CANTAT20
Galactocentric position diagram