Basel 4

(FSR 0825; Czernik22; MWSC 672; OCL 455)

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0.82 UTI
0.76
CN
0.69
Cdens
1.0
CC3
0.84
Clit
1.0
Cdup
Nm (P>50%) 123
Core radius and density 2.1 [pc], 3.4 [pc-2]
C3 classification AA
  • CN 0.76 Rich
  • Cdens 0.69 Moderately dense
  • CC3 1.0 Very high quality
  • Clit 0.84 Well-studied
  • Cdup 1.0 Unique
đŸ“Ĩ Members 📊 Colab đŸ”Ŧ Bayestar19 MOCAMOCA 🔍 CDS 🔍 Simbad 🔍 CDS (Îą, δ) 🔍 Simbad (Îą, δ)

Overview
ℹī¸
Basel 4 is a rich, moderately dense object of very high C3 quality. Its parallax locates it at a moderate distance, above the mid-plane, affected by moderate extinction. It is catalogued as a near-solar metallicity, intermediate-age cluster (see Parameters). It is well-studied in the literature.

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

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

Cavallo et al. (2024)
Gold sample.

Hunt & Reffert (2024)
Classified as open cluster. 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=0.208, e_all=0.1216.

Data
🔍 Search references for Basel 4 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– 87.242 30.194 0.293 0.837 -1.79 6.157
Li et al. 2025 87.242 30.19 0.286 0.835 -1.801 –
Almeida et al. 2025 87.235 30.194 – – – –
Zhang et al. 2024 87.243 30.192 – – – –
Hunt & Reffert 2024 87.243 30.192 0.3 0.821 -1.792 4.541
Cavallo et al. 2024 87.242 30.196 0.299 – – –
Hunt & Reffert 2023 87.243 30.192 0.3 0.821 -1.792 4.541
Just et al. 2023 87.242 30.206 – – – –
Netopil et al. 2022 87.242 30.189 0.278 0.846 -1.804 6.52
Dias et al. 2021 87.235 30.194 0.279 0.837 -1.809 6.533
Cantat-Gaudin et al. 2020 87.242 30.19 0.286 0.835 -1.801 –
Zhong et al. 2020 87.242 30.19 – 0.835 -1.801 4.466
Cantat-Gaudin & Anders 2020 87.242 30.19 0.286 0.835 -1.801 –
Bossini et al. 2019 87.242 30.19 – – – –
Soubiran et al. 2018 87.242 30.19 – – – 6.52
Bica et al. 2019 87.221 30.196 – – – –
Cantat-Gaudin et al. 2018 87.242 30.19 0.286 0.835 -1.801 –
Dias et al. 2018 – – – 2.48 -1.34 –
Kharchenko et al. 2016 87.242 30.206 – – – –
Dias et al. 2014 87.125 30.217 – -0.59 -2.65 –
Kharchenko et al. 2013 87.25 30.205 – -1.38 -6.37 –
Kharchenko et al. 2012 87.25 30.205 – -1.38 -6.37 –
Bukowiecki et al. 2011 87.237 30.182 – – – –
Froebrich et al. 2007 87.237 30.173 – – – –
van den Bergh 2006 87.125 30.217 – – – –
Dias et al. 2002 87.125 30.217 – -0.59 -2.65 –
Lynga 1987 87.126 30.217 – – – –

💡 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– 3.04 1.58 0.89 288 -0.175 670 – –
Li et al. 2025 2.85 1.64 – 288 -0.058 – – –
Almeida et al. 2025 2.83 1.78 – 198 – 320 – –
Zhang et al. 2024 – – – – -0.153(1) – – –
Hunt & Reffert 2024 2.95 1.33 0.89 339 – 975(1) – –
Cavallo et al. 2024 2.42 1.58 – 457 -0.290 – – –
Hunt & Reffert 2023 2.95 1.33 0.89 339 – – – –
Just et al. 2023 – – – 462 – 366 – –
Netopil et al. 2022 3.60(1) 1.74 – 158 -0.180(1) – – –
Dias et al. 2021 2.83 1.78 – 198 -0.175 – – –
Cantat-Gaudin et al. 2020 3.33 1.48 – 112 – – – –
Kounkel et al. 2020 3.04 1.67 – 295 – – – –
Zhong et al. 2020 3.17(1) 1.58 – 8665 -0.275 – – –
Cantat-Gaudin & Anders 2020 3.17 – – – – – – –
Bossini et al. 2019 3.40 1.52 – 136 0.000 – – –
Soubiran et al. 2018 3.17 – – – – – – –
Cantat-Gaudin et al. 2018 3.17 – – – – – – –
Kharchenko et al. 2016 2.80 1.58 – 462 – – – –
Kharchenko et al. 2013 2.80 1.58 – 462 – – – –
Bukowiecki et al. 2012 – – – – – 2029 – –
Kharchenko et al. 2012 2.80 1.58 – 462 – – – –
Bukowiecki et al. 2011 3.07(1) 1.42 – 178 – – – –
van den Bergh 2006 5.67 1.67 – 10 – – – –
Dias et al. 2002 3.00 1.42 – 200 – – – –
Lynga 1987 5.90 2.02 – 13 – – – –

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

Cluster % RA DEC Plx pmRA pmDE Rv UTI
OC 0295 48.0 87.24 30.19 0.3 0.84 -1.8 6.16 0.0

💡 Note: The % column shows the percentage of members that Basel 4 shares with each listed object.

Visualization
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Basel 4 UCC
Basel 4 HUNT23
Basel 4 CANTAT20
Galactocentric position diagram