NGC 6819

(Melotte 223; Collinder 403; MWSC 3155; OCL 155; FSR 0202; FoF 628)

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1.0 UTI
1.0
CN
1.0
Cdens
1.0
CC3
1.0
Clit
1.0
Cdup
Nm (P>50%) 2007
Core radius and density 1.8 [pc], 38 [pc-2]
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 6819 is a very rich, very dense object of very high C3 quality. Its parallax locates it at a moderate distance, above the mid-plane, affected by low extinction. It is catalogued as a very 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: 1.00 (50th percentile).

Rain et al. (2024)
The BSS population splits into two luminosity groups. Brighter BSSs are reproduced by binary evolution with higher-mass donors, while fainter ones follow lower-mass donor tracks. Overall agreement between models and observations is excellent, with some BSSs nearing MS turnoff.

Hunt & Reffert (2023)
Classified as open cluster. CMD class: 1.00 (50th percentile).

Hu et al. (2021)
Ellipticities (core, all): e_core=0.1038, e_all=0.1653.

Rain et al. (2021)
This object probably suffers from differential reddening. We suggest exploring this effect in future works.

Ahumada & Lapasset (2007)
The apparent cluster diameter is from (1970PDDO....4....1H). Several stragglers are pointed out in (1974A&AS...13..143A). Membership probabilities from (1972A&A....19..155S): star 32, 88%; star 35, 90%; star 36, 92%; star 40, 81%; star 55, 66%; star 59, 86%; star 65, 89%; star 70, 92%; star 96, 49%; star 103, 57%; star 118, 77%; star 6044, 33%. Attention is drawn in (1998AJ....115.1516R) on several clump stars that appear to be more massive than the turnoff stars: it is suggested that they are the descendants of blue stragglers.

Data
πŸ” Search references for NGC 6819 in: SciX Simbad
ℹ️
Reference Year RA [deg] DEC [deg] Plx [mas] pmRA [mas/yr] pmDE [mas/yr] Rv [km/s]
UCC 99999– 295.327 40.191 0.373 -2.894 -3.864 2.992
Bijavara Seshashayana et al. 2025 295.382 40.282 – – – –
Otto et al. 2026 295.322 40.19 – -2.92 -3.86 2.6
Nizovkina et al. 2025 295.322 40.19 – – – –
Li et al. 2025 295.327 40.19 0.356 -2.916 -3.856 –
Guerco et al. 2025 295.0 40.2 0.38 -2.85 -3.94 2.76
Hu & Soubiran 2025 295.326 40.192 – – – –
Wei et al. 2025 295.325 40.192 0.376 -2.893 -3.87 –
Carrasco-Varela et al. 2025 295.494 40.214 – – – –
Almeida et al. 2025 295.329 40.19 – – – –
Zhang et al. 2024 295.322 40.19 – – – –
Hunt & Reffert 2024 295.322 40.19 0.376 -2.9 -3.87 2.969
Cavallo et al. 2024 295.326 40.192 0.376 – – –
Rain et al. 2024 295.328 40.19 0.373 -2.894 -3.869 –
Hunt & Reffert 2023 295.322 40.19 0.376 -2.9 -3.87 2.969
Angelo et al. 2023 295.337 40.208 – -2.89 -3.87 –
Cordoni et al. 2023 295.329 40.19 0.357 -2.913 -3.856 –
Just et al. 2023 295.316 40.193 – – – –
Jadhav & Subramaniam 2021 295.327 40.19 – – – –
Jaehnig et al. 2021 295.324 40.192 0.384 -2.916 -3.858 –
Netopil et al. 2022 295.316 40.197 – – – 2.8
Rain et al. 2021 295.327 40.19 0.356 -2.916 -3.856 –
Dias et al. 2021 295.329 40.19 0.357 -2.913 -3.856 3.376
Spina et al. 2021 295.327 40.19 0.357 -2.909 -3.857 –
Cantat-Gaudin et al. 2020 295.327 40.19 0.356 -2.916 -3.856 –
SΓ‘nchez et al. 2020 295.317 40.197 – -2.893 -3.727 –
Donor et al. 2020 295.32 40.195 – -2.96 -3.87 2.7
Zhong et al. 2020 295.327 40.19 – -2.916 -3.856 -4.191
Cantat-Gaudin & Anders 2020 295.327 40.19 0.356 -2.916 -3.856 –
Liu & Pang 2019 295.329 40.191 0.357 -2.908 -3.865 –
Bossini et al. 2019 295.327 40.19 – – – –
Soubiran et al. 2018 295.327 40.19 – – – 3.31
Bica et al. 2019 295.333 40.175 – – – –
Cantat-Gaudin et al. 2018 295.327 40.19 0.356 -2.916 -3.856 –
Dias et al. 2018 – – – -3.38 -4.28 –
Loktin & Popova 2017 295.32 40.195 – -3.191 -0.848 1.0
Sampedro et al. 2017 295.317 40.197 – -5.41 -4.05 –
Kharchenko et al. 2016 295.316 40.193 – – – –
Netopil et al. 2016 295.325 40.187 – – – –
Dias et al. 2014 295.317 40.197 – -6.07 -3.57 –
Kharchenko et al. 2013 295.32 40.195 – -3.99 -0.3 1.0
Gozha et al. 2012 295.325 40.187 – – – –
Bukowiecki et al. 2011 295.312 40.199 – – – –
Kharchenko et al. 2007 295.32 40.19 – 0.04 – –
Ahumada & Lapasset 2007 295.325 40.183 – – – –
van den Bergh 2006 295.325 40.187 – – – –
Chen et al. 2003 295.319 40.197 – -3.14 -3.34 4.8
Dias et al. 2002 295.317 40.197 – -6.07 -3.57 2.3
Lynga 1987 295.339 40.183 – – – –
Sulentic et al. 1973 295.339 40.193 – – – –

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– 2.44 0.495 0.59 2239 0.050 7568 0.31 15
Bijavara Seshashayana et al. 2025 – 0.40 – 2240 -0.020(14) – – –
Otto et al. 2026 – – – 2239 0.040(15) – – –
Nizovkina et al. 2025 2.28(4) 0.60(4) – 2667(4) -0.108(4) – – –
Li et al. 2025 2.43 0.50 – 2583 0.056 – – –
Guerco et al. 2025 – – – 2240 0.040 – – –
Hu & Soubiran 2025 – – – – -0.100(5) – – –
Wei et al. 2025 2.06 0.22 – 3800 0.250 8717 0.58 –
Carrasco-Varela et al. 2025 2.44 0.49 – 2630 0.050 – – 14(1)
Almeida et al. 2025 2.44 0.49 – 2630 – 7277 – –
Zhang et al. 2024 – – – – 0.009(1) – – –
Hunt & Reffert 2024 2.52 0.32 0.59 1683 – 7568(1) – –
Cavallo et al. 2024 2.39 0.70 – 1995 0.000 – – –
Rain et al. 2024 2.13 0.39 – 4644 – 28157 0.18 –
Hunt & Reffert 2023 2.52 0.32 0.59 1683 – – – –
Angelo et al. 2023 2.40 0.50 – 2512 0.100 24(1) – –
Cordoni et al. 2023 2.44 0.49 – 2630 0.093 4061 0.31 15(1)
Just et al. 2023 – – – 1622 – 843 – –
Spina et al. 2022 – – – – 0.050 – – –
Jadhav & Subramaniam 2021 2.77 0.40 – 2239 – 14963 – 12(1)
Jaehnig et al. 2021 2.61(1) – – – – – – –
Netopil et al. 2022 2.75(1) – – 1995 0.050(1) – – –
Rain et al. 2021 2.60 0.50 – 2291 – – – 15
Dias et al. 2021 2.44 0.49 – 2630 0.093 – – –
Spina et al. 2021 2.80 – – 2239 0.058(20) – – –
Cantat-Gaudin et al. 2020 2.77 0.40 – 2239 – – – –
Kounkel et al. 2020 2.70 0.53 – 1778 – – – –
Donor et al. 2020 – – – – 0.050 – – –
Zhong et al. 2020 2.60(1) 0.48 – 9301 0.037 – – –
Cantat-Gaudin & Anders 2020 2.60 – – – – – – –
Liu & Pang 2019 – – – 3890 0.250 – – –
Bossini et al. 2019 2.71 0.47 – 2000 0.000 – – –
Soubiran et al. 2018 2.60 – – – – – – –
Cantat-Gaudin et al. 2018 2.60 – – – – – – –
Loktin & Popova 2017 2.41 0.73 – 1524 – – – –
Kharchenko et al. 2016 2.36 0.75 – 1622 – – – –
Netopil et al. 2016 7.69 – – 2110 0.090(2) – – –
Heiter et al. 2014 – – – – 0.090 – – –
Kharchenko et al. 2013 2.36 0.75 – 1622 0.090 – – –
Bukowiecki et al. 2012 – – – – – 8559 – –
Gozha et al. 2012 2.36 – – 1493 0.090 – – –
Bukowiecki et al. 2011 2.65(1) 0.22 – 1778 – – – –
Ahumada & Lapasset 2007 – 0.76 – 1479 – – – 29
van den Bergh 2006 2.36 0.76 – 1479 – – – –
Chen et al. 2003 2.36 0.75 – 1490 0.070(1) – – –
Dias et al. 2002 2.40 0.50 – 2291 -0.020 – – –
Lynga 1987 2.20 1.42 – 3467 -0.110 – – –

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

Visualization
ℹ️
NGC 6819 UCC
NGC 6819 HUNT23
NGC 6819 CANTAT20
Galactocentric position diagram