Melotte 81

(Collinder 171; NGC 2509; MWSC 1410; OCL 630; ESO 561 07; FSR 1282; FoF 588)

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0.98 UTI
0.88
CN
1.0
Cdens
1.0
CC3
1.0
Clit
1.0
Cdup
N50 (P>50% members) 442
Stellar density (N50/rad) 29.9 [N/pc2]
C3 classification AA
  • CN 0.88 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
Melotte 81 is a 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 massive, near-solar metallicity, old cluster, but with a large variance across recent sources for the absorption, metallicity, and mass parameters (see Parameters). It is very well-studied in the literature.

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

Cavallo et al. (2024)
Gold sample.

Data
πŸ” Search references for Melotte 81 in: SciX Simbad
ℹ️
Reference Year RA [deg] DEC [deg] Plx [mas] pmRA [mas/yr] pmDE [mas/yr] Rv [km/s]
UCC 99999– 120.202 -19.057 0.371 -2.72 0.798 60.613
Li et al. 2025 120.201 -19.056 0.363 -2.708 0.764 –
Hu & Soubiran 2025 120.201 -19.058 – – – –
Almeida et al. 2025 120.2 -19.058 – – – –
Hunt & Reffert 2024 120.201 -19.058 0.373 -2.72 0.804 58.708
Cavallo et al. 2024 120.201 -19.058 0.374 – – –
Hunt & Reffert 2023 120.201 -19.058 0.373 -2.72 0.804 58.708
Almeida et al. 2023 120.2 -19.058 – – – –
Just et al. 2023 120.189 -19.048 – – – –
Dias et al. 2021 120.2 -19.058 0.364 -2.708 0.766 61.087
Cantat-Gaudin et al. 2020 120.201 -19.056 0.363 -2.708 0.764 –
SΓ‘nchez et al. 2020 120.2 -19.052 – -2.759 0.752 –
Cantat-Gaudin & Anders 2020 120.201 -19.056 0.363 -2.708 0.764 –
Liu & Pang 2019 120.198 -19.056 0.369 -2.712 0.771 –
Soubiran et al. 2018 120.201 -19.056 – – – 60.83
Bica et al. 2019 120.193 -19.056 – – – –
Cantat-Gaudin et al. 2018 120.201 -19.056 0.363 -2.708 0.764 –
Loktin & Popova 2017 120.195 -19.05 – -6.133 2.19 –
Kharchenko et al. 2016 120.189 -19.048 – – – –
Dias et al. 2014 120.2 -19.052 – -2.64 1.81 –
Kharchenko et al. 2013 120.195 -19.05 – -3.82 4.24 –
Dias et al. 2002 120.2 -19.052 – -2.64 1.81 –

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– 2.46 0.32 0.16 1514 -0.021 1194 0.89 –
Li et al. 2025 2.50 0.35 – 1468 0.057 – – –
Hu & Soubiran 2025 – – – – -0.100(5) – – –
Almeida et al. 2025 2.41 0.33 – 1514 – 935 – –
Hunt & Reffert 2024 – – – – – 2169(1) – –
Cavallo et al. 2024 2.18 0.61 – 1479 -0.230 – – –
Hunt & Reffert 2023 2.42 0.12 0.16 1644 – – – –
Almeida et al. 2023 2.83 0.06 – 1400 0.426 1453(1) 0.89 –
Just et al. 2023 – – – 1585 – 255 – –
Dias et al. 2021 2.41 0.33 – 1514 0.082 – – –
Cantat-Gaudin et al. 2020 2.50 0.23 – 1514 – – – –
Cantat-Gaudin & Anders 2020 2.55 – – – – – – –
Liu & Pang 2019 – – – 2290 -0.500 – – –
Soubiran et al. 2018 2.55 – – – – – – –
Cantat-Gaudin et al. 2018 2.55 – – – – – – –
Loktin & Popova 2017 3.25 0.14 – 1288 – – – –
Kharchenko et al. 2016 1.71 0.32 – 1585 – – – –
Kharchenko et al. 2013 1.71 0.32 – 1585 – – – –
Dias et al. 2002 0.91 0.46 – 7943 – – – –

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

Visualization
ℹ️
Melotte 81 UCC
Melotte 81 HUNT23
Melotte 81 CANTAT20
Galactocentric position diagram