UPK 20

(OCSN 289)

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0.76 UTI
0.67
CN
1.0
Cdens
0.75
CC3
0.7
Clit
1.0
Cdup
C3 classification AB
Number of members (P>50%) 84
Radius (P>50% members) 27.0 [arcmin]
  • CN 0.67 Moderately populated
  • Cdens 1.0 Very dense
  • CC3 0.75 High quality
  • Clit 0.7 Moderately 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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UPK 20 is a moderately populated, very dense object of high C3 quality. Its parallax locates it at a very close distance, near the mid-plane, affected by moderate extinction. It is catalogued as a near-solar metallicity, intermediate-age cluster, but with a large variance across recent sources for the age parameter (see Parameters). It is moderately studied in the literature.

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

Very close Moderate extinction Near-solar metallicity Intermediate age

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

Cavallo et al. (2024)
Gold sample.

Data
🔍 Search references for UPK 20 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 – 281.105 -14.456 2.12 3.343 1.051 -6.574
Li et al. 2025 281.145 -14.456 2.105 3.336 1.145 –
Almeida et al. 2025 281.151 -14.536 – – – –
Alfonso et al. 2024 281.156 -14.491 2.071 3.329 1.083 –
Hunt & Reffert 2024 281.119 -14.374 2.123 3.339 1.058 -6.945
Cavallo et al. 2024 281.114 -14.551 2.127 – – –
Hunt & Reffert 2023 281.119 -14.374 2.123 3.339 1.058 -6.945
Qin et al. 2023 281.13 -14.43 2.1 3.42 1.07 -7.27
Tarricq et al. 2022 281.081 -14.283 2.106 3.307 1.052 –
Dias et al. 2021 281.151 -14.536 2.102 3.32 1.18 –
Cantat-Gaudin et al. 2020 281.145 -14.456 2.105 3.336 1.145 –
Cantat-Gaudin & Anders 2020 281.145 -14.471 2.107 3.336 1.208 –
Sim et al. 2019 281.133 -14.476 – 3.32 1.14 –

💡 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 0.43 1.86 – 248 0.030 – – –
Almeida et al. 2025 0.47 1.64 – 468 – 150 – –
Alfonso et al. 2024 0.49 0.96 – 1173 0.191 – – –
Hunt & Reffert 2024 – – – – – 179* – –
Cavallo et al. 2024 0.49 2.01 – 145 0.270 – – –
Hunt & Reffert 2023 0.45 1.88 2.50 146 – – – –
Qin et al. 2023 1.23 2.33 – 141 – – – –
Tarricq et al. 2022 0.49 – – 2239 – – – –
Dias et al. 2021 0.47 1.64 – 468 0.191 – – –
Cantat-Gaudin et al. 2020 0.49 0.96 – 2138 – – – –
Cantat-Gaudin & Anders 2020 0.47 – – – – – – –
Sim et al. 2019 0.47 – – 631 – – – –

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

Cluster % RA DEC Plx pmRA pmDE Rv UTI
CWWDL 14605 41.7 281.16 -14.44 2.12 3.31 1.04 -7.39 0.0

💡 Note: The % column shows the percentage of members that UPK 20 shares with each listed object.

Visualization
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UPK 20 UCC
UPK 20 HUNT23
UPK 20 CANTAT20
Galactocentric position diagram