NGC 6531

(Melotte 188; Collinder 363; MWSC 2796; M 21; OCL 26; ESO 521 19)

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0.96 UTI
0.79
CN
1.0
Cdens
1.0
CC3
1.0
Clit
1.0
Cdup
N50 (P>50% members) 205
Stellar density (N50/rad) 70.1 [N/pc2]
C3 classification AA
  • CN 0.79 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 6531 is a rich, very dense object of very high C3 quality. Its parallax locates it at a relatively close distance, near the mid-plane, affected by low extinction. It is catalogued as a near-solar metallicity, very young cluster, but with a large variance across recent sources for the absorption and mass parameters (see Parameters). It is very well-studied in the literature.

Liu et al. (2025)
Classified as primordial binary cluster 129 along with Collinder_367.

Palma et al. (2025)
Classified as genetic pair P216, along with HSC_106.

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

Cavallo et al. (2024)
Gold sample.

Hunt & Reffert (2024)
Classified as open cluster. CMD classes: 1.00 (50th percentile), true positive (human-assigned).

Rain et al. (2021)
This cluster was include in (Dias et al., 2002A&A...389..871D, Cat. B/ocl) however, parameters log(t)=7.873, Av=0.636, [Fe/H]=0.00 were taken from Bossini et al. (2019A&A...623A.108B, Cat. J/A+A/623/A108).

Morales et al. (2013)
Classified as morphological type 'OC2' (totally exposed cluster without correlation with ATLASGAL emission). Morphological flag: exposed cluster, without submm emission.

Data
πŸ” Search references for NGC 6531 in: SciX Simbad
ℹ️
Reference Year RA [deg] DEC [deg] Plx [mas] pmRA [mas/yr] pmDE [mas/yr] Rv [km/s]
UCC 99999– 271.046 -22.503 0.799 0.542 -1.45 -4.885
Almeida et al. 2025 271.031 -22.515 – – – –
Hunt & Reffert 2024 271.042 -22.5 0.801 0.538 -1.464 -5.191
Celli et al. 2024 271.036 -22.505 – – – –
Cavallo et al. 2024 271.041 -22.523 0.798 – – –
Hunt & Reffert 2023 271.042 -22.5 0.801 0.538 -1.464 -5.191
Just et al. 2023 271.042 -22.491 – – – –
He et al. 2022 271.036 -22.511 0.807 0.535 -1.476 –
Jaehnig et al. 2021 271.05 -22.495 0.841 0.472 -1.397 –
Rain et al. 2021 271.036 -22.505 0.798 0.525 -1.521 –
Richer et al. 2021 271.047 -22.507 0.81 0.394 -1.361 –
Dias et al. 2021 271.031 -22.515 0.797 0.537 -1.536 –
Spina et al. 2021 271.034 -22.504 0.802 0.532 -1.422 –
Cantat-Gaudin et al. 2020 271.036 -22.505 0.798 0.525 -1.521 –
SΓ‘nchez et al. 2020 271.054 -22.49 – 0.597 -1.404 –
Cantat-Gaudin & Anders 2020 271.036 -22.505 0.798 0.525 -1.521 –
Bossini et al. 2019 271.036 -22.505 – – – –
Bica et al. 2019 271.046 -22.494 – – – –
Cantat-Gaudin et al. 2018 271.036 -22.505 0.798 0.525 -1.521 –
Loktin & Popova 2017 271.05 -22.491 – 2.794 -2.952 -14.7
Kharchenko et al. 2016 271.042 -22.491 – – – –
Dias et al. 2014 271.054 -22.49 – 0.55 0.15 –
Kharchenko et al. 2013 271.05 -22.49 – 2.43 -1.44 -14.7
Morales et al. 2013 271.054 -22.49 – – – –
Gozha et al. 2012 271.054 -22.49 – – – –
Bukowiecki et al. 2011 271.012 -22.493 – – – –
Piskunov et al. 2008 271.046 -22.494 – – – –
Kharchenko et al. 2007 271.05 -22.49 – 0.3 – -14.71
Piskunov et al. 2007 271.046 -22.494 – – – –
Ahumada & Lapasset 2007 271.05 -22.483 – – – –
van den Bergh 2006 271.05 -22.483 – – – –
Kharchenko et al. 2005 271.05 -22.49 – 0.26 -2.66 -14.71
Kharchenko et al. 2003 271.05 -22.49 – -0.38 -2.47 –
Chen et al. 2003 271.109 -22.492 – 2.28 -3.05 -16.0
Dias et al. 2002 271.054 -22.49 – 2.28 -3.05 -13.49
Dambis 1999 271.054 -22.49 – – – –
Lynga 1987 271.157 -22.495 – – – -12.0
Sulentic et al. 1973 271.153 -22.498 – – – –

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– 1.21 0.88 1.3 11 0.000 668 – 0
Liu et al. 2025 1.49 0.28 – 11 – – – –
Almeida et al. 2025 1.16 0.99 – 13 – 446 – –
Hunt & Reffert 2024 – – – – – 913(1) – –
Celli et al. 2024 – – – 13 – 670 – –
Cavallo et al. 2024 1.08 0.98 – 9 -0.130 – – –
Hunt & Reffert 2023 1.19 0.80 1.30 5 – – – –
Just et al. 2023 – – – 7 – 117 – –
He et al. 2022 – 1.10 – 6 – – – –
Jaehnig et al. 2021 1.19(1) – – – – – – –
Rain et al. 2021 1.21 0.76 – 11 – – – 0
Richer et al. 2021 – 1.61 – 12 – – – –
Dias et al. 2021 1.16 0.99 – 13 0.090 – – –
Spina et al. 2021 1.25 – – 13 – – – –
Cantat-Gaudin et al. 2020 1.16 0.67 – 13 – – – –
Kounkel et al. 2020 1.19 1.13 – 11 – – – –
Cantat-Gaudin & Anders 2020 1.21 – – – – – – –
Bossini et al. 2019 1.09 0.76 – 11 0.000 – – –
Cantat-Gaudin et al. 2018 1.21 – – – – – – –
Loktin & Popova 2017 1.21 0.89 – 12 – – – –
Kharchenko et al. 2016 1.19 1.09 – 7 – – – –
Kharchenko et al. 2013 1.19 1.09 – 7 – – – –
Morales et al. 2013 1.21 – – 12 – – – –
Bukowiecki et al. 2012 – – – – – 667 – –
Gozha et al. 2012 1.21 – – 12 – 2512 – –
Bukowiecki et al. 2011 0.80(1) 0.76 – 16 – – – –
Piskunov et al. 2008 1.21 0.88 – 7 – 783(1) – –
Piskunov et al. 2007 1.21 0.88 – 7 – 170 – –
Ahumada & Lapasset 2007 – 0.88 – 12 – – – 0
van den Bergh 2006 1.21 0.88 – 12 – – – –
Kharchenko et al. 2005 1.21 0.88 – 7 – – – –
Kharchenko et al. 2003 1.21 0.79 – – – – – –
Chen et al. 2003 1.21 – – 10 – – – –
Dias et al. 2002 1.21 0.89 – 12 – – – –
Dambis 1999 1.03 0.88 – 4 – – – –
Lynga 1987 1.30 0.91 – 5 – – – –

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

Visualization
ℹ️
NGC 6531 UCC
NGC 6531 HUNT23
NGC 6531 CANTAT20
Galactocentric position diagram