Trumpler 18

(MWSC 1911; FoF 1526)

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0.90 UTI
0.77
CN
1.0
Cdens
0.75
CC3
1.0
Clit
1.0
Cdup
C3 classification AB
Number of members (P>50%) 158
Radius (P>50% members) 5.0 [arcmin]
  • CN 0.77 Rich
  • Cdens 1.0 Very dense
  • CC3 0.75 High quality
  • Clit 1.0 Very well-studied
  • Cdup 1.0 Unique
đŸ“Ĩ Members 📊 Colab đŸ”Ŧ Bayestar19 🔍 CDS 🔍 Simbad 🔍 CDS (Îą, δ) 🔍 Simbad (Îą, δ)

Overview
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Trumpler 18 is a rich, very dense object of 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, young cluster, but with a large variance across recent sources for the age and mass parameters (see Parameters). It is very well-studied in the literature.
Relatively close Low extinction Near-solar metallicity Young

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

Cavallo et al. (2024)
Gold sample.

Data
🔍 Search references for Trumpler 18 in: SciX Simbad
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Reference Year RA [deg] DEC [deg] Plx [mas] pmRA [mas/yr] pmDE [mas/yr] Rv [km/s]
UCC – 167.83 -60.637 0.65 -7.147 0.609 -8.602
Li et al. 2025 167.826 -60.656 0.624 -7.172 0.569 –
Wei et al. 2025 167.858 -60.644 0.657 -7.159 0.621 –
Almeida et al. 2025 167.832 -60.652 – – – –
Hunt & Reffert 2024 167.826 -60.63 0.654 -7.138 0.623 40.181
Cavallo et al. 2024 167.844 -60.655 0.655 – – –
Hunt & Reffert 2023 167.826 -60.63 0.654 -7.138 0.623 40.181
Just et al. 2023 167.888 -60.661 – – – –
Tarricq et al. 2022 167.833 -60.657 0.664 -7.137 0.612 –
Jaehnig et al. 2021 167.827 -60.655 0.663 -7.161 0.567 –
Rain et al. 2021 167.826 -60.656 0.624 -7.172 0.569 –
Dias et al. 2021 167.832 -60.652 0.622 -7.165 0.571 –
Cantat-Gaudin et al. 2020 167.826 -60.656 0.624 -7.172 0.569 –
Cantat-Gaudin & Anders 2020 167.826 -60.656 0.624 -7.172 0.569 –
Liu & Pang 2019 167.803 -60.639 0.63 -7.146 0.561 –
Dias et al. 2019 167.867 -60.667 0.633 -7.168 0.583 -4.6
Bossini et al. 2019 167.826 -60.656 – – – –
Cantat-Gaudin et al. 2018 167.826 -60.656 0.624 -7.172 0.569 –
Loktin & Popova 2017 167.865 -60.667 – -7.22 2.13 -17.4
Kharchenko et al. 2016 167.888 -60.661 – – – –
Dias et al. 2014 167.867 -60.667 – -4.07 -0.88 –
Kharchenko et al. 2013 167.895 -60.665 – -8.9 0.6 -17.4
Gozha et al. 2012 167.867 -60.667 – – – –
Piskunov et al. 2008 167.877 -60.664 – – – –
Kharchenko et al. 2007 167.86 -60.67 – 0.16 – -20.0
van den Bergh 2006 167.875 -60.667 – – – –
Kharchenko et al. 2005 167.88 -60.67 – -9.13 0.52 -20.0
Kharchenko et al. 2003 167.88 -60.67 – -9.12 0.07 –
Dias et al. 2002 167.867 -60.667 – -4.07 -0.88 -20.0
Dambis 1999 167.867 -60.667 – – – –

💡 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] Bfr BSS
Li et al. 2025 1.39 0.89 – 71 -0.053 – – –
Wei et al. 2025 2.13 1.33 – 35 -0.250 439 0.34 –
Almeida et al. 2025 1.49 0.90 – 86 – 181 – –
Hunt & Reffert 2024 – – – – – 951* – –
Cavallo et al. 2024 1.40 0.94 – 91 -0.010 – – –
Hunt & Reffert 2023 1.45 0.69 0.96 102 – – – –
Just et al. 2023 – – – 49 – 122 – –
Tarricq et al. 2022 1.46 – – 58 – – – –
Jaehnig et al. 2021 1.50* – – – – – – –
Rain et al. 2021 1.53 0.96 – 15 – – – 0
Dias et al. 2021 1.49 0.90 – 86 0.155 – – –
Cantat-Gaudin et al. 2020 1.52 0.76 – 48 – – – –
Cantat-Gaudin & Anders 2020 1.53 – – – – – – –
Liu & Pang 2019 – – – 34 -0.250 – – –
Dias et al. 2019 1.55 0.71 – 48 0.112 – – –
Bossini et al. 2019 1.65 0.91 – 46 0.000 – – –
Cantat-Gaudin et al. 2018 1.53 – – – – – – –
Loktin & Popova 2017 1.36 0.97 – 16 – – – –
Kharchenko et al. 2016 1.42 0.82 – 49 – – – –
Kharchenko et al. 2013 1.42 0.82 – 49 – – – –
Gozha et al. 2012 1.36 – – 16 – 209 – –
Piskunov et al. 2008 1.36 0.96 – 59 – – – –
van den Bergh 2006 1.36 0.99 – 15 – – – –
Kharchenko et al. 2005 1.36 0.96 – 59 – – – –
Kharchenko et al. 2003 1.36 0.99 – – – – – –
Dias et al. 2002 1.36 0.98 – 16 – – – –
Dambis 1999 2.00 1.11 – 20 – – – –

(*): Indicates that this parameter is assigned more than one value in the corresponding reference.

Visualization
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Trumpler 18 UCC
Trumpler 18 HUNT23
Trumpler 18 CANTAT20
Galactocentric position diagram