UPK 552

(OCSN 315)

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0.44 UTI
0.37
CN
0.26
Cdens
0.75
CC3
0.42
Clit
1.0
Cdup
Nm (P>50%) 37
Core radius and density 1.8 [pc], 1.3 [pc-2]
C3 classification BA
  • CN 0.37 Poorly populated
  • Cdens 0.26 Loose
  • CC3 0.75 High quality
  • Clit 0.42 Poorly studied
  • Cdup 1.0 Unique
đŸ“Ĩ Members 📊 Colab đŸ”Ŧ Bayestar19 MOCAMOCA 🔍 CDS 🔍 Simbad 🔍 CDS (Îą, δ) 🔍 Simbad (Îą, δ)

Overview
ℹī¸
UPK 552 is a poorly populated, loose object of high C3 quality. Its parallax locates it at a very close distance, above the mid-plane, affected by low extinction. It is catalogued as a near-solar metallicity, intermediate-age cluster, but with a large variance across recent sources for the absorption, age, and metallicity parameters (see Parameters). It is poorly studied in the literature.

Liu et al. (2025)
Classified as primordial binary cluster 224 along with HSC_2263.

Palma et al. (2025)
Part of multiple system G149, along with HSC_2263 and HSC_2307.

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

Cavallo et al. (2024)
Gold sample.

Hunt & Reffert (2024)
Classified as moving group. CMD class: 1.00 (50th percentile).

Hunt & Reffert (2023)
Classified as open cluster. CMD class: 1.00 (50th percentile).

Hu et al. (2021)
Ellipticities (core, all): e_core=0.258, e_all=0.4491.

Data
🔍 Search references for UPK 552 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 99999– 158.498 -47.229 3.074 -22.479 6.497 4.749
Li et al. 2025 158.509 -47.263 3.056 -22.634 6.34 –
Almeida et al. 2025 158.547 -47.243 – – – –
Alfonso et al. 2024 158.395 -47.18 3.049 -22.519 6.595 –
Cavallo et al. 2024 158.908 -47.225 3.169 – – –
Hunt & Reffert 2023 158.46 -46.986 3.166 -23.087 6.501 3.594
Almeida et al. 2023 158.628 -47.422 – – – –
Qin et al. 2023 158.39 -47.08 3.07 -22.57 6.45 9.18
He et al. 2022 158.302 -47.082 3.076 -22.516 6.572 –
Tarricq et al. 2022 158.54 -47.106 3.071 -22.444 6.359 –
Dias et al. 2021 158.547 -47.243 3.048 -22.57 6.35 7.675
Spina et al. 2021 158.498 -47.297 3.053 -22.638 6.375 –
Cantat-Gaudin et al. 2020 158.509 -47.263 3.056 -22.634 6.34 –
Cantat-Gaudin & Anders 2020 158.509 -47.263 3.066 -22.561 6.38 –
Sim et al. 2019 158.704 -47.287 – -22.45 6.31 –

💡 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– 0.33 0.13 0.34 102 -0.032 70 0.68 –
Liu et al. 2025 0.38 0.10 – 89 – – – –
Li et al. 2025 0.33 0.19 – 96 -0.032 – – –
Almeida et al. 2025 0.32 0.13 – 192 – 45 – –
Alfonso et al. 2024 0.33 0.00 – 75 -0.040 – – –
Cavallo et al. 2024 0.33 0.36 – 65 0.380 – – –
Hunt & Reffert 2023 0.30 0.08 0.34 108 – – – –
Almeida et al. 2023 0.33 0.10 – 274 0.006 95(1) 0.68 –
Qin et al. 2023 0.34 0.22 – 79 – – – –
He et al. 2022 – 0.35 – 71 – – – –
Tarricq et al. 2022 0.32 – – 120 – – – –
Dias et al. 2021 0.32 0.13 – 192 -0.040 – – –
Spina et al. 2021 0.33 – – 117 – – – –
Cantat-Gaudin et al. 2020 0.33 0.00 – 117 – – – –
Cantat-Gaudin & Anders 2020 0.32 – – – – – – –
Sim et al. 2019 0.34 – – 89 – – – –

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

Visualization
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UPK 552 UCC
UPK 552 HUNT23
UPK 552 CANTAT20
Galactocentric position diagram