Trumpler 23

(Collinder 295; VDBH 180; MWSC 2343; OCL 950; vdBergh-Hagen 180; ESO 178 06)

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0.94 UTI
1.0
CN
1.0
Cdens
1.0
CC3
0.84
Clit
1.0
Cdup
Nm (P>50%) 750
Core radius and density 1.4 [pc], 25 [pc-2]
C3 classification AA
  • CN 1.0 Very rich
  • Cdens 1.0 Very dense
  • CC3 1.0 Very high quality
  • Clit 0.84 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
Trumpler 23 is a very rich, very dense object of very high C3 quality. Its parallax locates it at a moderate distance, near the mid-plane, affected by moderate extinction. It is catalogued as a massive, near-solar metallicity, intermediate-age cluster, but with a large variance across recent sources for the distance, metallicity, and mass parameters (see Parameters). It is well-studied in the literature.

Note: This object contains blue stragglers according to at least one source.

Liu et al. (2025)
Classified as tidal capture (resonant trapping binary) 343 along with Teutsch_247.

Palma et al. (2025)
Classified as optical pair P66, along with Teutsch_247.

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

Cavallo et al. (2024)
Gold sample.

Hunt & Reffert (2024)
Classified as open cluster. CMD class: 0.98 (50th percentile).

Hunt & Reffert (2023)
Classified as open cluster. CMD class: 0.98 (50th percentile).

Hu et al. (2021)
Ellipticities (core, all): e_core=0.0302, e_all=0.1067.

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 Trumpler 23 in: SciX Simbad
ℹ️
Reference Year RA [deg] DEC [deg] Plx [mas] pmRA [mas/yr] pmDE [mas/yr] Rv [km/s]
UCC 99999– 240.218 -53.538 0.363 -4.208 -4.758 -60.974
Li et al. 2025 240.218 -53.539 0.352 -4.178 -4.746 –
Hu & Soubiran 2025 240.222 -53.54 – – – –
Carrasco-Varela et al. 2025 240.551 -53.608 – – – –
Almeida et al. 2025 240.214 -53.544 – – – –
Hunt & Reffert 2024 240.214 -53.537 0.367 -4.21 -4.758 -48.477
Cavallo et al. 2024 240.222 -53.54 0.367 – – –
Hunt & Reffert 2023 240.214 -53.537 0.367 -4.21 -4.758 -48.477
Just et al. 2023 240.205 -53.532 – – – –
Jadhav & Subramaniam 2021 240.218 -53.539 – – – –
Dias et al. 2021 240.214 -53.544 0.349 -4.162 -4.748 -63.27
Cantat-Gaudin et al. 2020 240.218 -53.539 0.352 -4.178 -4.746 –
SΓ‘nchez et al. 2020 240.204 -53.536 – -4.012 -4.929 –
Cantat-Gaudin & Anders 2020 240.218 -53.539 0.352 -4.178 -4.746 –
Soubiran et al. 2018 240.218 -53.539 – – – -61.43
Bica et al. 2019 240.196 -53.532 – – – –
Cantat-Gaudin et al. 2018 240.218 -53.539 0.352 -4.178 -4.746 –
Dias et al. 2018 – – – -3.57 -4.31 –
Sampedro et al. 2017 240.204 -53.536 – -2.16 -4.51 –
Kharchenko et al. 2016 240.205 -53.532 – – – –
Dias et al. 2014 240.204 -53.536 – -2.42 -4.31 –
Kharchenko et al. 2013 240.217 -53.533 – -5.67 -4.96 –
Morales et al. 2013 240.204 -53.536 – – – –
Dias et al. 2002 240.204 -53.536 – -2.42 -4.31 –
Lynga 1987 240.113 -53.521 – – – –
van den Bergh & Hagen 1975 239.15 -53.383 – – – –

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– 2.48 2.33 1.54 708 0.175 3720 – 2
Liu et al. 2025 7.31 0.93 – 407 – – – –
Li et al. 2025 2.38 2.52 – 670 0.253 – – –
Hu & Soubiran 2025 – – – – -0.170(5) – – –
Carrasco-Varela et al. 2025 2.59 2.28 – 708 0.350 – – 2(1)
Almeida et al. 2025 2.23 2.73 – 292 – 3218 – –
Hunt & Reffert 2024 2.48 2.84 1.54 332 – 6307(1) – –
Cavallo et al. 2024 1.85 2.83 – 871 -0.260 – – –
Hunt & Reffert 2023 2.48 2.84 1.54 332 – – – –
Just et al. 2023 – – – 912 – 326 – –
Spina et al. 2022 – – – – 0.223 – – –
Jadhav & Subramaniam 2021 2.59 2.18 – 708 – 4221 – 2(1)
Dias et al. 2021 2.23 2.73 – 292 0.127 – – –
Cantat-Gaudin et al. 2020 2.59 2.18 – 708 – – – –
Kounkel et al. 2020 2.77 2.38 – 692 – – – –
Cantat-Gaudin & Anders 2020 2.63 – – – – – – –
Soubiran et al. 2018 2.63 – – – – – – –
Cantat-Gaudin et al. 2018 2.63 – – – – – – –
Kharchenko et al. 2016 2.19 1.91 – 912 – – – –
Kharchenko et al. 2013 2.19 1.91 – 912 – – – –
Morales et al. 2013 1.90 – – 900 – – – –
Dias et al. 2002 1.90 1.83 – 891 – – – –

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

Visualization
ℹ️
Trumpler 23 UCC
Trumpler 23 HUNT23
Trumpler 23 CANTAT20
Galactocentric position diagram