Melotte 40

(Collinder 81; NGC 2158; MWSC 733; OCL 468; FSR 0872; FoF 367)

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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) 2029
Stellar density (N50/rad) 219.6 [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
Melotte 40 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 moderate extinction. It is catalogued as an extremely 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.

Note: This object shares a very small percentage of members with a later reported entry. See table with shared members information.

Cavallo et al. (2024)
Gold sample.

Rain et al. (2024)
Several BSS candidates lie blueward of the ZAMS, possibly due to misclassification or photometric errors. Excluding these, the remaining BSSs and the YSS are well matched by binary evolutionary tracks.

Data
πŸ” Search references for Melotte 40 in: SciX Simbad
ℹ️
Reference Year RA [deg] DEC [deg] Plx [mas] pmRA [mas/yr] pmDE [mas/yr] Rv [km/s]
UCC 99999– 91.862 24.098 0.23 -0.198 -1.982 26.473
Li et al. 2025 91.862 24.099 0.192 -0.177 -2.002 –
Hu & Soubiran 2025 91.862 24.099 – – – –
Zhang et al. 2024 91.859 24.098 – – – –
Hunt & Reffert 2024 91.859 24.098 0.233 -0.211 -1.982 26.962
Cavallo et al. 2024 91.862 24.099 0.233 – – –
Rain et al. 2024 91.862 24.099 0.231 -0.193 -1.978 –
Hunt & Reffert 2023 91.859 24.098 0.233 -0.211 -1.982 26.962
Just et al. 2023 91.848 24.093 – – – –
Jaehnig et al. 2021 91.862 24.099 0.205 -0.2 -2.004 –
Rain et al. 2021 91.862 24.099 0.192 -0.177 -2.002 –
Cantat-Gaudin et al. 2020 91.862 24.099 0.192 -0.177 -2.002 –
SΓ‘nchez et al. 2020 91.854 24.097 – -0.257 -1.99 –
Donor et al. 2020 91.857 24.092 – -0.24 -2.0 27.7
Cantat-Gaudin & Anders 2020 91.862 24.099 0.192 -0.177 -2.002 –
Liu & Pang 2019 91.862 24.104 0.281 -0.096 -1.943 –
Soubiran et al. 2018 91.862 24.099 – – – 26.65
Bica et al. 2019 91.857 24.091 – – – –
Cantat-Gaudin et al. 2018 91.862 24.099 0.192 -0.177 -2.002 –
Loktin & Popova 2017 91.86 24.098 – 0.002 -0.849 28.0
Kharchenko et al. 2016 91.848 24.093 – – – –
Dias et al. 2014 91.854 24.097 – -1.22 -3.3 –
Kharchenko et al. 2013 91.857 24.092 – -0.29 -2.48 28.0
Gozha et al. 2012 91.854 24.097 – – – –
Glushkova et al. 2010 91.866 24.098 – – – –
Kharchenko et al. 2007 91.86 24.1 – 0.04 – –
van den Bergh 2006 91.854 24.097 – – – –
Chen et al. 2003 91.857 24.091 – – – –
Dias et al. 2002 91.854 24.097 – -1.22 -3.3 26.9

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– 4.54 1.14 1.18 1876 -0.243 20923 0.37 39.0
Li et al. 2025 3.98 1.61 – 1894 -0.246 – – –
Hu & Soubiran 2025 – – – – -0.240(5) – – –
Zhang et al. 2024 – – – – -0.322(1) – – –
Hunt & Reffert 2024 – – – – – 20923(1) – –
Cavallo et al. 2024 3.34 1.37 – 2512 -0.010 – – –
Rain et al. 2024 3.59 1.33 – 3057 – 38854 0.37 –
Hunt & Reffert 2023 3.80 1.37 1.18 1858 – – – –
Just et al. 2023 – – – 2138 – 3819 – –
Jaehnig et al. 2021 5.07(1) – – – – – – –
Rain et al. 2021 4.54 1.12 – 1047 – – – 39
Cantat-Gaudin et al. 2020 4.31 1.44 – 1549 – – – –
Donor et al. 2020 – – – – -0.210 – – –
Cantat-Gaudin & Anders 2020 4.54 – – – – – – –
Liu & Pang 2019 – – – 1200 0.500 – – –
Soubiran et al. 2018 4.54 – – – – – – –
Cantat-Gaudin et al. 2018 4.54 – – – – – – –
Loktin & Popova 2017 5.12 1.14 – 1107 – – – –
Kharchenko et al. 2016 4.77 1.03 – 2138 – – – –
Kharchenko et al. 2013 4.77 1.03 – 2138 -0.250 – – –
Gozha et al. 2012 5.07 – – 1054 -0.250 – – –
Glushkova et al. 2010 3.30 1.05 – 1995 – – – –
van den Bergh 2006 5.07 1.12 – 1047 – – – –
Chen et al. 2003 3.60 1.71 – 2000 -0.230(1) – – –
Dias et al. 2002 5.07 1.12 – 1054 -0.280 – – –

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

Cluster % RA DEC Plx pmRA pmDE Rv UTI
OC 0306 1.2 91.87 24.1 0.36 -0.2 -2.02 – 0.0

πŸ’‘ Note: The % column shows the percentage of members that Melotte 40 shares with each listed object.

Visualization
ℹ️
Melotte 40 UCC
Melotte 40 HUNT23
Melotte 40 CANTAT20
Galactocentric position diagram