Berkeley 102

(MWSC 3750; OCL 263)

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0.68 UTI
0.78
CN
0.45
Cdens
0.75
CC3
0.71
Clit
1.0
Cdup
Nm (P>50%) 181
Core radius and density 2.8 [pc], 2.2 [pc-2]
C3 classification AB
  • CN 0.78 Rich
  • Cdens 0.45 Loose
  • CC3 0.75 High quality
  • Clit 0.71 Moderately studied
  • Cdup 1.0 Unique
đŸ“Ĩ Members 📊 Colab đŸ”Ŧ Bayestar19 MOCAMOCA 🔍 CDS 🔍 Simbad 🔍 CDS (Îą, δ) 🔍 Simbad (Îą, δ)

Overview
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Berkeley 102 is a rich, loose object of high C3 quality. Its parallax locates it at a very large distance, well below the mid-plane, affected by moderate extinction. It is catalogued as a massive, near-solar metallicity, old cluster, but with a large variance across recent sources for the age, metallicity, and mass parameters (see Parameters). It is moderately studied in the literature.

Cavallo et al. (2024)
Gold sample.

Hunt & Reffert (2024)
Classified as open cluster. CMD class: 0.20 (50th percentile).

Hunt & Reffert (2023)
Classified as open cluster. CMD class: 0.20 (50th percentile).

Perren et al. (2022)
A controversial object: Maciejewski 2008 concluded it is a chance alignment of unrelated stars. However, the CMD shows a scattered main sequence with the TO at G=18.5 and a well-defined giant branch, leading us to classify it as a genuine open cluster. The four catalogs span wildly different distances (2.6–10.5 kpc) and ages (0.6–4 Gyr). ASteCA gives 7.4 kpc and 4.9 Gyr. The age is close to CG20 (3.9 Gyr) but the distance is ~3 kpc smaller, placing the cluster below 9 kpc.

Hu et al. (2021)
Ellipticities (core, all): e_core=0.3427, e_all=0.1314.

Data
🔍 Search references for Berkeley 102 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– 354.663 56.639 0.088 -1.534 -0.366 -126.974
Li et al. 2025 354.66 56.637 0.05 -1.559 -0.34 –
Hu & Soubiran 2025 354.639 56.63 – – – –
Hunt & Reffert 2024 354.671 56.64 0.101 -1.549 -0.342 -85.772
Cavallo et al. 2024 354.639 56.63 0.095 – – –
Hunt & Reffert 2023 354.671 56.64 0.101 -1.549 -0.342 -85.772
Just et al. 2023 354.707 56.622 – – – –
Perren et al. 2022 354.66 56.637 – – – –
Jadhav & Subramaniam 2021 354.66 56.637 – – – –
Cantat-Gaudin et al. 2020 354.66 56.637 0.05 -1.559 -0.34 –
Cantat-Gaudin & Anders 2020 354.66 56.637 0.05 -1.559 -0.34 –
Bica et al. 2019 354.664 56.643 – – – –
Cantat-Gaudin et al. 2018 354.66 56.637 0.05 -1.559 -0.34 –
Loktin & Popova 2017 354.675 56.633 – -1.63 -0.44 –
Sampedro et al. 2017 354.675 56.633 – -4.22 0.35 –
Kharchenko et al. 2016 354.707 56.622 – – – –
Tadross 2014 354.675 56.633 – – – –
Kharchenko et al. 2013 354.715 56.626 – -3.89 -1.87 –
Gozha et al. 2012 354.675 56.633 – – – –
Kharchenko et al. 2012 354.715 56.626 – -3.89 -1.87 –
Bukowiecki et al. 2011 354.679 56.642 – – – –
Dias et al. 2002 354.675 56.633 – -1.63 -0.44 –
Lynga 1987 354.681 56.646 – – – –

💡 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– 8.355 1.56 1.62 1445 -0.350 1110 0.55 0
Li et al. 2025 8.57 1.44 – 2402 0.049 – – –
Hu & Soubiran 2025 – – – – -0.320(5) – – –
Hunt & Reffert 2024 8.56 1.78 1.62 1413 – 1110(1) – –
Cavallo et al. 2024 7.83 1.21 – 3631 0.040 – – –
Hunt & Reffert 2023 8.56 1.78 1.62 1413 – – – –
Just et al. 2023 – – – 1380 – 692 – –
Perren et al. 2022 7.35 1.42 – 4898 -0.170 5800 0.55 –
Jadhav & Subramaniam 2021 10.52 1.11 – 3890 – 6556 – 0(1)
Cantat-Gaudin et al. 2020 10.52 1.11 – 3890 – – – –
Kounkel et al. 2020 8.15 1.56 – 1445 – – – –
Cantat-Gaudin & Anders 2020 12.61 – – – – – – –
Cantat-Gaudin et al. 2018 12.61 – – – – – – –
Loktin & Popova 2017 1.75 1.95 – 5012 – – – –
Kharchenko et al. 2016 4.90 1.89 – 1380 – – – –
Tadross 2014 2.60 2.18 – 600 – – – –
Kharchenko et al. 2013 4.90 1.89 – 1380 -0.380 – – –
Bukowiecki et al. 2012 – – – – – 167 – –
Gozha et al. 2012 9.64 – – 3162 -0.380 – – –
Kharchenko et al. 2012 4.90 1.89 – 1380 -0.380 – – –
Bukowiecki et al. 2011 2.50(1) 1.29 – 1000 – – – –
Dias et al. 2002 9.64 1.29 – 3162 -0.380 – – –

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

Visualization
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Berkeley 102 UCC
Berkeley 102 HUNT23
Berkeley 102 CANTAT20
Galactocentric position diagram