Ruprecht 66

(VDBH 41; MWSC 1530; OCL 732; vdBergh-Hagen 41; ESO 313 08; FSR 1388)

0.85 UTI

0.83

C_N

1.0

C_dens

1.0

C_C3

0.71

C_lit

1.0

C_dup

N_m (P>50%) 321

Core radius and density 1.2 [pc], 14 [pc^-2]

C3 classification AA

C_N 0.83 Rich
C_dens 1.0 Very dense
C_C3 1.0 Very high quality
C_lit 0.71 Moderately studied
C_dup 1.0 Unique

📥 Members 📊 Colab 🔬 Bayestar19

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

Overview

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Ruprecht 66 is a rich, very 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 massive, near-solar metallicity, old cluster, but with a large variance across recent sources for the mass parameter (see Parameters). It is moderately studied in the literature.

Note: This object contains blue stragglers according to at least one source.

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

Distant Moderate extinction Massive Near-solar metallicity Old Contains BSS

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

Cavallo et al. (2024)
Gold sample.

Hunt & Reffert (2024)
Classified as open cluster. CMD class: 0.99 (50th percentile).

Hunt & Reffert (2023)
Classified as open cluster. CMD class: 0.99 (50th percentile).

Hu et al. (2021)
Ellipticities (core, all): e_core=0.0998, e_all=0.0777.

Data

🔍 Search references for Ruprecht 66 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–	130.143	-38.069	0.233	-3.099	3.089	38.079
Li et al.	2025	130.142	-38.071	0.222	-3.115	3.085	–
Hu & Soubiran	2025	130.143	-38.073	–	–	–	–
Almeida et al.	2025	130.15	-38.074	–	–	–	–
Hunt & Reffert	2024	130.134	-38.072	0.245	-3.097	3.086	38.846
Cavallo et al.	2024	130.143	-38.073	0.246	–	–	–
Hunt & Reffert	2023	130.134	-38.072	0.245	-3.097	3.086	38.846
Almeida et al.	2023	130.152	-38.068	–	–	–	–
Just et al.	2023	130.112	-38.052	–	–	–	–
Jadhav & Subramaniam	2021	130.142	-38.071	–	–	–	–
Dias et al.	2021	130.15	-38.074	0.223	-3.13	3.076	44.424
Cantat-Gaudin et al.	2020	130.142	-38.071	0.222	-3.115	3.085	–
Cantat-Gaudin & Anders	2020	130.142	-38.071	0.222	-3.115	3.085	–
Soubiran et al.	2018	130.142	-38.071	–	–	–	47.17
Bica et al.	2019	130.126	-38.073	–	–	–	–
Cantat-Gaudin et al.	2018	130.142	-38.071	0.222	-3.115	3.085	–
Sampedro et al.	2017	130.142	-38.08	–	-1.64	3.58	–
Kharchenko et al.	2016	130.112	-38.052	–	–	–	–
Dias et al.	2014	130.142	-38.08	–	-1.8	3.2	–
Kharchenko et al.	2013	130.117	-38.055	–	-6.37	9.67	–
Bukowiecki et al.	2011	130.137	-38.069	–	–	–	–
Dias et al.	2002	130.142	-38.08	–	-1.8	3.2	–
Lynga	1987	130.128	-38.059	–	–	–	–
van den Bergh & Hagen	1975	129.65	-37.883	–	–	–	–

💡 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–	3.9	1.765	1.55	1211	-0.110	1329	0.72	1
Li et al.	2025	4.16	1.68	–	1196	0.058	–	–	–
Hu & Soubiran	2025	–	–	–	–	-0.160⁽⁵⁾	–	–	–
Almeida et al.	2025	4.13	1.91	–	1211	–	1329	–	–
Hunt & Reffert	2024	3.68	1.50	1.55	1645	–	2806⁽¹⁾	–	–
Cavallo et al.	2024	3.16	1.85	–	1349	-0.110	–	–	–
Hunt & Reffert	2023	3.68	1.50	1.55	1644	–	–	–	–
Almeida et al.	2023	4.15	1.96	–	1074	-0.144	1220⁽¹⁾	0.72	–
Just et al.	2023	–	–	–	813	–	525	–	–
Jadhav & Subramaniam	2021	3.66	1.54	–	1413	–	1583	–	1⁽¹⁾
Dias et al.	2021	4.13	1.91	–	1211	-0.100	–	–	–
Cantat-Gaudin et al.	2020	3.66	1.54	–	1413	–	–	–	–
Kounkel et al.	2020	4.23	1.60	–	832	–	–	–	–
Cantat-Gaudin & Anders	2020	3.99	–	–	–	–	–	–	–
Soubiran et al.	2018	3.99	–	–	–	–	–	–	–
Cantat-Gaudin et al.	2018	3.99	–	–	–	–	–	–	–
Kharchenko et al.	2016	3.55	2.43	–	813	–	–	–	–
Kharchenko et al.	2013	3.55	2.43	–	813	–	–	–	–
Bukowiecki et al.	2011	3.90⁽¹⁾	1.29	–	1259	–	–	–	–
Dias et al.	2002	3.76	2.84	–	603	–	–	–	–

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

Cluster	%	RA	DEC	Plx	pmRA	pmDE	Rv	UTI
CKCWDM 54928	7.2	130.04	-37.97	0.21	-3.1	2.92	34.64	0.09
CKCWDM 55081	0.9	130.39	-38.21	0.14	-2.92	3.42	63.77	0.02

💡 Note: The % column shows the percentage of members that Ruprecht 66 shares with each listed object.

Visualization

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