Ruprecht 138

(NGC 6506; MWSC 2771; OCL 16; ESO 521 06)

0.89 UTI

0.79

C_N

1.0

C_dens

1.0

C_C3

0.84

C_lit

1.0

C_dup

N₅₀ (P>50% members) 217

Stellar density (N₅₀/rad) 32.4 [N/pc²]

C3 classification AA

C_N 0.79 Rich
C_dens 1.0 Very dense
C_C3 1.0 Very high quality
C_lit 0.84 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 138 is a rich, very dense object of very high C3 quality. Its parallax locates it at a moderate distance, near 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 age, metallicity, and mass parameters (see Parameters). It is well-studied in the literature.

Relatively close Moderate extinction Near-solar metallicity Intermediate age

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

Cavallo et al. (2024)
Gold sample.

Data

🔍 Search references for Ruprecht 138 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–	269.996	-24.664	0.382	0.264	-1.137	7.775
Almeida et al.	2025	269.983	-24.668	–	–	–	–
Hunt & Reffert	2024	269.992	-24.663	0.394	0.271	-1.142	11.615
Celli et al.	2024	269.984	-24.665	–	–	–	–
Cavallo et al.	2024	269.987	-24.657	0.394	–	–	–
Hunt & Reffert	2023	269.992	-24.663	0.394	0.271	-1.142	11.615
Just et al.	2023	269.982	-24.699	–	–	–	–
Dias et al.	2021	269.983	-24.668	0.364	0.252	-1.149	–
Cantat-Gaudin et al.	2020	269.984	-24.665	0.369	0.248	-1.147	–
Cantat-Gaudin & Anders	2020	269.984	-24.665	0.369	0.248	-1.147	–
Soubiran et al.	2018	269.984	-24.665	–	–	–	-10.54
Bica et al.	2019	269.966	-24.681	–	–	–	–
Cantat-Gaudin et al.	2018	269.984	-24.665	0.369	0.248	-1.147	–
Kharchenko et al.	2016	269.982	-24.699	–	–	–	–
Dias et al.	2014	269.983	-24.683	–	-2.25	-3.91	–
Kharchenko et al.	2013	269.991	-24.698	–	-1.43	-2.67	–
Dias et al.	2002	269.983	-24.683	–	-2.25	-3.91	–

💡 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–	2.26	2.28	2.36	142	-0.013	856	–	–
Almeida et al.	2025	2.26	2.35	–	13	–	626	–	–
Hunt & Reffert	2024	–	–	–	–	–	1822⁽¹⁾	–	–
Celli et al.	2024	–	–	–	10	–	1087	–	–
Cavallo et al.	2024	1.98	2.98	–	178	-0.230	–	–	–
Hunt & Reffert	2023	2.29	2.59	2.36	105	–	–	–	–
Just et al.	2023	–	–	–	794	–	17	–	–
Dias et al.	2021	2.26	2.35	–	13	0.203	–	–	–
Cantat-Gaudin et al.	2020	2.73	2.21	–	10	–	–	–	–
Cantat-Gaudin & Anders	2020	2.51	–	–	–	–	–	–	–
Soubiran et al.	2018	2.51	–	–	–	–	–	–	–
Cantat-Gaudin et al.	2018	2.51	–	–	–	–	–	–	–
Kharchenko et al.	2016	1.13	2.19	–	794	–	–	–	–
Kharchenko et al.	2013	1.13	2.19	–	794	–	–	–	–
Dias et al.	2002	0.93	0.56	–	1995	–	–	–	–

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

Visualization

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