Ruprecht 4

(Berkeley 74; MWSC 990; OCL 560; FSR 1165)

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0.91 UTI
0.79
CN
1.0
Cdens
0.75
CC3
1.0
Clit
1.0
Cdup
C3 classification AB
Number of members (P>50%) 210
Radius (P>50% members) 3.3 [arcmin]
  • CN 0.79 Rich
  • Cdens 1.0 Very dense
  • CC3 0.75 High quality
  • Clit 1.0 Very well-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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Ruprecht 4 is a rich, very dense object of high C3 quality. Its parallax locates it at a moderate distance, below 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 mass parameter (see Parameters). It is very well-studied in the literature.

Note: This object shares a small percentage of members with 2 later reported entries. See table with shared members information.

Distant Moderate 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 Ruprecht 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 – 102.247 -10.526 0.218 -0.213 0.103 46.421
Li et al. 2025 102.248 -10.524 0.214 -0.197 0.096 –
Hu & Soubiran 2025 102.235 -10.52 – – – –
Almeida et al. 2025 102.243 -10.529 – – – –
Hunt & Reffert 2024 102.245 -10.53 0.211 -0.215 0.098 46.518
Cavallo et al. 2024 102.235 -10.52 0.213 – – –
Hunt & Reffert 2023 102.245 -10.53 0.211 -0.215 0.098 46.518
Almeida et al. 2023 102.24 -10.529 – – – –
Just et al. 2023 102.234 -10.508 – – – –
Dias et al. 2021 102.243 -10.529 0.209 -0.205 0.126 –
Cantat-Gaudin et al. 2020 102.248 -10.524 0.214 -0.197 0.096 –
Cantat-Gaudin & Anders 2020 102.248 -10.524 0.214 -0.197 0.096 –
Bica et al. 2019 102.248 -10.514 – – – –
Cantat-Gaudin et al. 2018 102.248 -10.524 0.214 -0.197 0.096 –
Loktin & Popova 2017 102.24 -10.51 – 0.562 0.347 47.5
Kharchenko et al. 2016 102.234 -10.508 – – – –
Dias et al. 2014 102.225 -10.533 – 0.94 -4.3 –
Kharchenko et al. 2013 102.24 -10.51 – 1.79 2.17 47.5
Gozha et al. 2012 102.225 -10.533 – – – –
Dias et al. 2002 102.225 -10.533 – 0.94 -4.3 47.5

💡 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 3.65 1.51 – 851 -0.154 – – –
Hu & Soubiran 2025 – – – – -0.250* – – –
Almeida et al. 2025 3.60 1.67 – 643 – 482 – –
Hunt & Reffert 2024 – – – – – 1660* – –
Cavallo et al. 2024 3.18 1.55 – 977 -0.240 – – –
Hunt & Reffert 2023 3.87 1.46 1.63 574 – – – –
Almeida et al. 2023 3.58 1.67 – 708 -0.175 738* 0.70 –
Just et al. 2023 – – – 1012 – 989 – –
Dias et al. 2021 3.60 1.67 – 643 -0.100 – – –
Cantat-Gaudin et al. 2020 4.09 1.24 – 851 – – – –
Cantat-Gaudin & Anders 2020 4.12 – – – – – – –
Cantat-Gaudin et al. 2018 4.12 – – – – – – –
Loktin & Popova 2017 5.82 1.73 – 631 – – – –
Kharchenko et al. 2016 4.59 1.42 – 1012 – – – –
Kharchenko et al. 2013 4.59 1.42 – 1012 -0.090 – – –
Gozha et al. 2012 4.70 – – 794 -0.090 – – –
Dias et al. 2002 4.70 0.93 – 794 -0.090 – – –

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

Cluster % RA DEC Plx pmRA pmDE Rv UTI
OC 0371 14.3 102.24 -10.53 0.24 -0.2 0.1 48.23 0.0
OC 0372 11.9 102.24 -10.52 0.23 -0.21 0.1 48.23 0.0

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

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