Ruprecht 21

(MWSC 1225)

0.18 UTI

0.0

C_N

0.01

C_dens

0.25

C_C3

0.31

C_lit

1.0

C_dup

C3 classification CC

Number of members (P>50%) 13

Radius (P>50% members) 8.6 [arcmin]

C_N 0.0 Sparse
C_dens 0.01 Very loose
C_C3 0.25 Low quality
C_lit 0.31 Poorly studied
C_dup 1.0 Unique

📥 Members 📊 Colab 🔬 Bayestar19 🔍 CDS 🔍 Simbad 🔍 CDS (α, δ) 🔍 Simbad (α, δ)

Overview

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Ruprecht 21 is a sparse, very loose object of low C3 quality. Its parallax locates it at a large^* distance, well below the mid-plane, affected by moderate extinction. It is catalogued as a massive, intermediate-age cluster (see Parameters). It is poorly studied in the literature.

(*): The parallax distance estimate (~7.69 kpc) differs significantly from the median photometric distance (~3.89 kpc).

⚠️ Warning: the low UTI value and no obvious signs of duplication (C_dup=1.0) indicate that this is quite probably an asterism, moving group, or artifact, and not a real open cluster.

Distant Moderate extinction Massive Intermediate age

Data

🔍 Search references for Ruprecht 21 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	–	111.79	-31.163	0.13	-0.82	2.685	89.315
Just et al.	2023	111.73	-31.152	–	–	–	–
Loktin & Popova	2017	111.735	-31.183	–	-3.832	2.148	–
Kharchenko et al.	2016	111.73	-31.152	–	–	–	–
Dias et al.	2014	111.733	-31.183	–	-2.28	4.03	–
Kharchenko et al.	2013	111.735	-31.155	–	-3.34	2.31	–

💡 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
Just et al.	2023	–	–	–	447	–	1660	–	–
Loktin & Popova	2017	2.26	0.45	–	2188	–	–	–	–
Kharchenko et al.	2016	3.89	2.39	–	447	–	–	–	–
Kharchenko et al.	2013	3.89	2.39	–	447	–	–	–	–

Visualization

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