OC 0521

0.17 UTI

0.27

C_N

0.18

C_dens

0.25

C_C3

0.06

C_lit

1.0

C_dup

N_m (P>50%) 27

Core radius and density 1.6 [pc], 0.9 [pc^-2]

C3 classification DB

C_N 0.27 Poorly populated
C_dens 0.18 Very loose
C_C3 0.25 Low quality
C_lit 0.06 Rarely studied
C_dup 1.0 Unique

📥 Members 📊 Colab 🔬 Bayestar19

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

Overview

ℹ️

OC 0521 is a poorly populated, very loose object of low 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, young cluster, but with a large variance across recent sources for the age and metallicity parameters (see Parameters). It is rarely studied in the literature.

⚠️ 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.

Relatively close Moderate extinction Near-solar metallicity Young

Palma et al. (2025)
Classified as optical pair P392, along with Gulliver_27.

Cavallo et al. (2024)
Gold sample.

Hunt & Reffert (2024)
Classified as open cluster. CMD class: 0.56 (50th percentile).

Hunt & Reffert (2023)
Classified as open cluster. CMD class: 0.56 (50th percentile).

Data

🔍 Search references for OC 0521 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–	144.925	-54.043	0.354	-5.457	4.522	–
Hunt & Reffert	2024	144.965	-54.042	0.331	-5.429	4.502	–
Cavallo et al.	2024	144.748	-53.994	0.333	–	–	–
Hunt & Reffert	2023	144.965	-54.042	0.331	-5.429	4.502	–
Hao et al.	2022	144.956	-54.072	0.352	-5.539	4.563	–

💡 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–	2.68	2.74	1.97	33	0.374	306	–	–
Hunt & Reffert	2024	2.68	2.69	1.97	33	–	306⁽¹⁾	–	–
Cavallo et al.	2024	2.77	2.79	–	98	0.700	–	–	–
Hunt & Reffert	2023	2.68	2.69	1.97	33	–	–	–	–
Hao et al.	2022	–	2.86	–	10	0.049	–	–	–

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

Visualization

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