NGC 6940

(Melotte 232; Collinder 424; MWSC 3370; OCL 141; FoF 2054)

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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) 808
Stellar density (N50/rad) 45.1 [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
đŸ“Ĩ Members 📊 Colab đŸ”Ŧ Bayestar19 MOCAMOCA 🔍 CDS 🔍 Simbad 🔍 CDS (Îą, δ) 🔍 Simbad (Îą, δ)

Overview
ℹī¸
NGC 6940 is a very rich, very dense object of very high C3 quality. Its parallax locates it at a relatively close distance, below the mid-plane, affected by low extinction. It is catalogued as a massive, near-solar metallicity, intermediate-age 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.

Malhotra et al. (2026)
Lowest/Highest stellar mass in the catalogue with a mass-ratio estimate: 0.5/1.83 Msun

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: 1.00 (50th percentile).

Rain et al. (2021)
This cluster was include in (Dias et al., 2002A&A...389..871D, Cat. B/ocl) however, parameters log(t)=9.010, Av =0.455, [Fe/H]=+ 0.150 were taken from Bossini et al. (2019A&A...623A.108B, Cat. J/A+A/623/A108). Apparently, star Gaia DR2 1857459766532229248 is a massive straggler.

Ahumada & Lapasset (2007)
The following membership probabilities are from (1972A&A....16...58S): star 50, 83%; star 70, 90%; star 153, 90%; star 172=HD 334735, 89%; star 175, 85%; star 179=HD 334755, 83%. Some spectra: star 50, F0 (1957AJ.....62..175V); star 70, F5II-III (1958ApJ...128..562W); star 153, A0 (1960StoAn..20i...1L); star 175, A5 (1960StoAn..20i...1L); star 179, A0 (1960StoAn..20i...1L). Stars 70 and 77 are cited as blue stragglers in (1988PASP..100..338G).

Data
🔍 Search references for NGC 6940 in: SciX Simbad
ℹī¸
Reference Year RA [deg] DEC [deg] Plx [mas] pmRA [mas/yr] pmDE [mas/yr] Rv [km/s]
UCC 99999– 308.639 28.284 0.956 -1.952 -9.431 8.069
Malhotra et al. 2026 308.618 28.285 – – – –
Li et al. 2025 308.626 28.278 0.947 -1.954 -9.413 –
Hu & Soubiran 2025 308.633 28.292 – – – –
Wei et al. 2025 308.634 28.28 0.961 -1.939 -9.43 –
Almeida et al. 2025 308.615 28.273 – – – –
Hunt & Reffert 2024 308.591 28.258 0.958 -1.954 -9.437 8.023
Cavallo et al. 2024 308.633 28.292 0.959 – – –
Hunt & Reffert 2023 308.591 28.258 0.958 -1.954 -9.437 8.023
Almeida et al. 2023 308.557 28.304 – – – –
Cordoni et al. 2023 308.615 28.273 0.95 -1.958 -9.411 –
Just et al. 2023 308.604 28.277 – – – –
He et al. 2022 308.628 28.294 0.958 -1.949 -9.437 –
Tarricq et al. 2022 308.626 28.249 0.959 -1.941 -9.43 –
Jadhav & Subramaniam 2021 308.626 28.278 – – – –
Jaehnig et al. 2021 308.619 28.269 0.977 -1.977 -9.415 –
Rain et al. 2021 308.626 28.278 0.947 -1.954 -9.413 –
Dias et al. 2021 308.615 28.273 0.95 -1.958 -9.411 8.047
Cantat-Gaudin et al. 2020 308.626 28.278 0.947 -1.954 -9.413 –
Cantat-Gaudin & Anders 2020 308.626 28.278 0.947 -1.954 -9.413 –
Liu & Pang 2019 308.632 28.299 0.951 -1.971 -9.398 –
Bossini et al. 2019 308.626 28.278 – – – –
Soubiran et al. 2018 308.626 28.278 – – – 8.1
Bica et al. 2019 308.612 28.317 – – – –
Cantat-Gaudin et al. 2018 308.626 28.278 0.947 -1.954 -9.413 –
Loktin & Popova 2017 308.61 28.283 – -0.935 -1.834 4.7
Kharchenko et al. 2016 308.604 28.277 – – – –
Dias et al. 2014 308.608 28.283 – -3.4 -4.47 –
Kharchenko et al. 2013 308.61 28.28 – -1.6 -8.69 4.7
Gozha et al. 2012 308.608 28.283 – – – –
Piskunov et al. 2008 308.604 28.273 – – – –
Kharchenko et al. 2007 308.61 28.28 – 0.5 – 4.66
Piskunov et al. 2007 308.604 28.273 – – – –
Ahumada & Lapasset 2007 308.6 28.283 – – – –
van den Bergh 2006 308.6 28.283 – – – –
Kharchenko et al. 2005 308.61 28.28 – -1.5 -8.93 4.42
Kharchenko et al. 2003 308.62 28.28 – -1.74 -9.11 –
Chen et al. 2003 308.656 28.302 – -2.23 -9.7 7.7
Dias et al. 2002 308.608 28.283 – -3.4 -4.47 7.89
Lynga 1987 308.647 28.308 – – – 4.0
Sulentic et al. 1973 308.637 28.303 – – – –

💡 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– 0.99 0.66 0.67 934 0.010 1302 0.43 2
Malhotra et al. 2026 1.01 0.45 – 975 0.009 – – –
Li et al. 2025 0.97 0.58 – 1209 -0.050 – – –
Hu & Soubiran 2025 – – – – -0.120(5) – – –
Wei et al. 2025 0.98 0.30 – 912 0.500 1356 0.32 –
Almeida et al. 2025 0.99 0.69 – 1175 – 1293 – –
Hunt & Reffert 2024 – – – – – 2132(1) – –
Cavallo et al. 2024 1.06 0.78 – 851 0.170 – – –
Hunt & Reffert 2023 0.99 0.45 0.67 769 – – – –
Almeida et al. 2023 1.00 0.71 – 1052 0.008 1393(1) 0.49 –
Cordoni et al. 2023 0.99 0.69 – 1175 -0.032 1310 0.43 1(1)
Just et al. 2023 – – – 955 – 149 – –
He et al. 2022 – 0.80 – 891 – – – –
Tarricq et al. 2022 1.07 – – 1380 – – – –
Jadhav & Subramaniam 2021 1.10 0.41 – 1349 – 2698 – 2(1)
Jaehnig et al. 2021 1.03(1) – – – – – – –
Rain et al. 2021 1.02 0.66 – 708 – – – 2
Dias et al. 2021 0.99 0.69 – 1175 -0.032 – – –
Cantat-Gaudin et al. 2020 1.10 0.41 – 1349 – – – –
Kounkel et al. 2020 1.03 0.88 – 724 – – – –
Cantat-Gaudin & Anders 2020 1.02 – – – – – – –
Liu & Pang 2019 – – – 1950 -0.500 – – –
Bossini et al. 2019 1.03 0.46 – 1023 0.150 – – –
Soubiran et al. 2018 1.02 – – – – – – –
Cantat-Gaudin et al. 2018 1.02 – – – – – – –
Loktin & Popova 2017 0.84 0.65 – 757 – – – –
Kharchenko et al. 2016 0.84 0.66 – 955 – – – –
Kharchenko et al. 2013 0.84 0.66 – 955 0.013 – – –
Gozha et al. 2012 0.77 – – 721 0.010 363 – –
Piskunov et al. 2008 0.77 0.66 – 871 – 589(1) – –
Piskunov et al. 2007 0.77 0.66 – 871 – 185 – –
Ahumada & Lapasset 2007 – 0.66 – 724 – – – 6
van den Bergh 2006 0.77 0.66 – 724 – – – –
Kharchenko et al. 2005 0.77 0.66 – 871 – – – –
Kharchenko et al. 2003 0.77 0.66 – – – – – –
Chen et al. 2003 0.77 0.68 – 720 0.010(1) – – –
Dias et al. 2002 0.77 0.68 – 721 0.013 – – –
Lynga 1987 0.80 0.76 – 1096 0.040 – – –

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

Visualization
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NGC 6940 UCC
NGC 6940 HUNT23
NGC 6940 CANTAT20
Galactocentric position diagram