Ruprecht 4

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

0.74 UTI

0.79

C_N

0.57

C_dens

0.75

C_C3

0.81

C_lit

1.0

C_dup

N_m (P>50%) 210

Core radius and density 2.3 [pc], 2.8 [pc^-2]

C3 classification AB

C_N 0.79 Rich
C_dens 0.57 Moderately dense
C_C3 0.75 High quality
C_lit 0.81 Well-studied
C_dup 1.0 Unique

📥 Members 📊 Colab 🔬 Bayestar19

MOCA 🔍 CDS 🔍 Simbad 🔍 CDS (α, δ) 🔍 Simbad (α, δ)

Overview

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Ruprecht 4 is a rich, moderately 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 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.

Hunt & Reffert (2024)
Classified as open cluster. CMD class: 0.98 (50th percentile).

Hunt & Reffert (2023)
Classified as open cluster. CMD class: 0.98 (50th percentile).

Hu et al. (2021)
Ellipticities (core, all): e_core=0.2927, e_all=0.1089.

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	99999–	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	–	–	–	–
Jadhav & Subramaniam	2021	102.248	-10.524	–	–	–	–
Netopil et al.	2022	102.225	-10.533	–	–	–	47.5
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
Sampedro et al.	2017	102.225	-10.533	–	0.87	-3.8	–
Kharchenko et al.	2016	102.234	-10.508	–	–	–	–
Netopil et al.	2016	102.24	-10.51	–	–	–	–
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	–	–	–	–
Bukowiecki et al.	2011	102.246	-10.512	–	–	–	–
Dias et al.	2002	102.225	-10.533	–	0.94	-4.3	47.5
Lynga	1987	102.216	-10.541	–	–	–	–

💡 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]	B_frac	BSS
UCC	99999–	4.09	1.46	1.63	851	-0.100	692	0.7	0
Li et al.	2025	3.65	1.51	–	851	-0.154	–	–	–
Hu & Soubiran	2025	–	–	–	–	-0.250⁽⁵⁾	–	–	–
Almeida et al.	2025	3.60	1.67	–	643	–	482	–	–
Hunt & Reffert	2024	3.87	1.45	1.63	574	–	1660⁽¹⁾	–	–
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⁽¹⁾	0.70	–
Just et al.	2023	–	–	–	1012	–	989	–	–
Jadhav & Subramaniam	2021	4.09	1.24	–	851	–	645	–	0⁽¹⁾
Netopil et al.	2022	4.09⁽¹⁾	–	–	851	-0.100⁽¹⁾	–	–	–
Dias et al.	2021	3.60	1.67	–	643	-0.100	–	–	–
Cantat-Gaudin et al.	2020	4.09	1.24	–	851	–	–	–	–
Kounkel et al.	2020	4.12	1.71	–	589	–	–	–	–
Cantat-Gaudin & Anders	2020	4.12	–	–	–	–	–	–	–
Cantat-Gaudin et al.	2018	4.12	–	–	–	–	–	–	–
Loktin & Popova	2017	5.82	1.76	–	631	–	–	–	–
Kharchenko et al.	2016	4.59	1.44	–	1012	–	–	–	–
Netopil et al.	2016	11.63	–	–	1030	–	–	–	–
Kharchenko et al.	2013	4.59	1.44	–	1012	-0.090	–	–	–
Bukowiecki et al.	2012	–	–	–	–	–	547	–	–
Gozha et al.	2012	4.70	–	–	794	-0.090	–	–	–
Bukowiecki et al.	2011	3.97⁽¹⁾	0.69	–	1122	–	–	–	–
Dias et al.	2002	4.70	0.95	–	794	-0.090	–	–	–

(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 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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