UPK 31

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0.67 UTI
0.56
CN
1.0
Cdens
0.5
CC3
0.65
Clit
1.0
Cdup
C3 classification BB
Number of members (P>50%) 63
Radius (P>50% members) 19.7 [arcmin]
  • CN 0.56 Moderately populated
  • Cdens 1.0 Very dense
  • CC3 0.5 Intermediate quality
  • Clit 0.65 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 31 is a moderately populated, very dense object of intermediate C3 quality. Its parallax locates it at a close distance, near the mid-plane, affected by low extinction. It is catalogued as a near-solar metallicity, intermediate-age cluster (see Parameters). It is moderately studied in the literature.

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

Close Low extinction Near-solar metallicity Intermediate age

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

Cavallo et al. (2024)
Gold sample.

Data
🔍 Search references for UPK 31 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 – 285.919 -8.458 1.841 -0.289 1.169 -16.336
Li et al. 2025 285.913 -8.51 1.823 -0.28 1.216 –
Almeida et al. 2025 285.908 -8.574 – – – –
Alfonso et al. 2024 285.957 -8.458 1.795 -0.294 1.169 –
Hunt & Reffert 2024 285.922 -8.483 1.822 -0.278 1.176 -17.605
Cavallo et al. 2024 285.936 -8.38 1.828 – – –
Hunt & Reffert 2023 285.922 -8.483 1.822 -0.278 1.176 -17.605
Tarricq et al. 2022 285.876 -8.442 1.858 -0.292 1.118 –
Dias et al. 2021 285.908 -8.574 1.827 -0.281 1.203 -16.265
Cantat-Gaudin et al. 2020 285.913 -8.51 1.823 -0.28 1.216 –
Cantat-Gaudin & Anders 2020 285.924 -8.532 1.83 -0.299 1.198 –
Sim et al. 2019 285.952 -8.484 – -0.32 1.21 –

💡 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 0.60 0.78 – 581 0.126 – – –
Almeida et al. 2025 0.54 0.83 – 618 – 81 – –
Alfonso et al. 2024 0.54 0.61 – 657 0.006 – – –
Hunt & Reffert 2024 – – – – – 103* – –
Cavallo et al. 2024 0.55 1.05 – 339 0.130 – – –
Hunt & Reffert 2023 0.52 0.64 1.10 426 – – – –
Tarricq et al. 2022 0.53 – – 501 – – – –
Dias et al. 2021 0.54 0.83 – 618 0.006 – – –
Cantat-Gaudin et al. 2020 0.54 0.61 – 501 – – – –
Cantat-Gaudin & Anders 2020 0.54 – – – – – – –
Sim et al. 2019 0.54 – – 35 – – – –

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

Cluster % RA DEC Plx pmRA pmDE Rv UTI
CWWDL 14601 71.4 285.91 -8.49 1.87 -0.3 1.17 -15.72 0.0

💡 Note: The % column shows the percentage of members that UPK 31 shares with each listed object.

Visualization
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UPK 31 UCC
UPK 31 HUNT23
UPK 31 CANTAT20
Galactocentric position diagram