Ruprecht 18

(MWSC 1211; FoF 32)

0.97 UTI

0.86

C_N

1.0

C_dens

1.0

C_C3

1.0

C_lit

1.0

C_dup

N₅₀ (P>50% members) 386

Stellar density (N₅₀/rad) 24.1 [N/pc²]

C3 classification AA

C_N 0.86 Rich
C_dens 1.0 Very dense
C_C3 1.0 Very high quality
C_lit 1.0 Very 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 18 is a rich, very dense object of very high C3 quality. Its parallax locates it at a moderate distance, below the mid-plane, affected by moderate extinction. It is catalogued as a massive, near-solar metallicity, intermediate-age cluster, but with a large variance across recent sources for the metallicity and mass parameters (see Parameters). It is very well-studied in the literature.

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

Relatively close Moderate extinction Massive Near-solar metallicity Intermediate age

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

Cavallo et al. (2024)
Gold sample.

Data

🔍 Search references for Ruprecht 18 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–	111.159	-26.209	0.378	-0.461	1.154	38.366
Almeida et al.	2025	111.152	-26.224	–	–	–	–
Hunt & Reffert	2024	111.164	-26.207	0.382	-0.465	1.165	36.134
Cavallo et al.	2024	111.137	-26.225	0.383	–	–	–
Hunt & Reffert	2023	111.164	-26.207	0.382	-0.465	1.165	36.134
Almeida et al.	2023	111.158	-26.23	–	–	–	–
Just et al.	2023	111.174	-26.208	–	–	–	–
Dias et al.	2021	111.152	-26.224	0.369	-0.493	1.107	31.487
Cantat-Gaudin et al.	2020	111.16	-26.213	0.364	-0.487	1.127	–
Cantat-Gaudin & Anders	2020	111.16	-26.213	0.364	-0.487	1.127	–
Liu & Pang	2019	111.149	-26.21	0.367	-0.517	1.136	–
Dias et al.	2019	111.162	-26.217	0.372	-0.495	1.159	31.403
Soubiran et al.	2018	111.16	-26.213	–	–	–	31.52
Cantat-Gaudin et al.	2018	111.16	-26.213	0.364	-0.487	1.127	–
Loktin & Popova	2017	111.165	-26.217	–	-3.694	1.445	31.0
Kharchenko et al.	2016	111.174	-26.208	–	–	–	–
Dias et al.	2014	111.162	-26.217	–	-1.45	2.43	–
Kharchenko et al.	2013	111.18	-26.21	–	-2.48	1.58	31.0
Gozha et al.	2012	111.163	-26.217	–	–	–	–
van den Bergh	2006	111.2	-26.217	–	–	–	–
Chen et al.	2003	111.16	-26.209	–	–	–	–
Dias et al.	2002	111.162	-26.217	–	-1.45	2.43	–
Dambis	1999	111.162	-26.217	–	–	–	–

💡 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]	B_frac	BSS
UCC	99999–	2.26	2.13	2.48	130	-0.010	1256	0.64	–
Almeida et al.	2025	2.26	1.95	–	130	–	1248	–	–
Hunt & Reffert	2024	–	–	–	–	–	2240⁽¹⁾	–	–
Cavallo et al.	2024	2.49	2.03	–	269	0.380	–	–	–
Hunt & Reffert	2023	2.40	1.84	2.48	161	–	–	–	–
Almeida et al.	2023	2.31	2.13	–	145	-0.053	1263⁽¹⁾	0.64	–
Just et al.	2023	–	–	–	285	–	72	–	–
Dias et al.	2021	2.26	1.95	–	130	0.123	–	–	–
Cantat-Gaudin et al.	2020	2.65	1.43	–	129	–	–	–	–
Cantat-Gaudin & Anders	2020	2.54	–	–	–	–	–	–	–
Liu & Pang	2019	–	–	–	214	-0.750	–	–	–
Dias et al.	2019	2.32	1.77	–	47	-1.335	–	–	–
Soubiran et al.	2018	2.54	–	–	–	–	–	–	–
Cantat-Gaudin et al.	2018	2.54	–	–	–	–	–	–	–
Loktin & Popova	2017	1.18	2.18	–	35	–	–	–	–
Kharchenko et al.	2016	1.50	2.13	–	285	–	–	–	–
Kharchenko et al.	2013	1.50	2.13	–	285	-0.010	–	–	–
Gozha et al.	2012	1.06	–	–	44	0.030	–	–	–
van den Bergh	2006	1.06	2.17	–	45	–	–	–	–
Chen et al.	2003	1.06	2.17	–	40	-0.010⁽¹⁾	–	–	–
Dias et al.	2002	1.06	2.17	–	44	-0.010	–	–	–
Dambis	1999	1.02	2.30	–	79	–	–	–	–

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

Cluster	%	RA	DEC	Plx	pmRA	pmDE	Rv	UTI
FSR 1300	88.6	111.16	-26.22	0.38	-0.46	1.16	38.53	0.02

💡 Note: The % column shows the percentage of members that Ruprecht 18 shares with each listed object.

Visualization

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