CWNU 509

0.18 UTI

0.26

C_N

0.03

C_dens

0.5

C_C3

0.06

C_lit

1.0

C_dup

N_m (P>50%) 26

Core radius and density 4.0 [pc], 0.1 [pc^-2]

C3 classification BB

C_N 0.26 Poorly populated
C_dens 0.03 Very loose
C_C3 0.5 Intermediate 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

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CWNU 509 is a poorly populated, very loose object of intermediate C3 quality. Its parallax locates it at a close distance, above the mid-plane, affected by low extinction. It is catalogued as a near-solar metallicity, intermediate-age cluster, but with a large variance across recent sources for the age and metallicity parameters (see Parameters). It is rarely studied in the literature.

Note: This object shares a moderate percentage of members with at least one entry reported in the same catalogue. See table with shared members information.

⚠️ 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.

Close Low extinction Near-solar metallicity Intermediate age

Cavallo et al. (2024)
Gold sample.

Hunt & Reffert (2024)
Classified as moving group. CMD class: 0.34 (50th percentile).

Hunt & Reffert (2023)
Classified as open cluster. CMD class: 0.34 (50th percentile).

Data

🔍 Search references for CWNU 509 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–	133.934	-25.675	1.043	-6.429	2.711	9.943
Hu & Soubiran	2025	133.907	-25.627	–	–	–	–
Cavallo et al.	2024	133.907	-25.627	1.038	–	–	–
Hunt & Reffert	2023	133.968	-25.541	1.037	-6.406	2.763	10.398
He et al.	2022	133.892	-25.954	1.05	-6.47	2.71	–

💡 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–	0.93	0.25	0.8	875	-0.240	–	–	–
Hu & Soubiran	2025	–	–	–	–	-0.240⁽⁵⁾	–	–	–
Cavallo et al.	2024	0.92	0.55	–	1047	0.070	–	–	–
Hunt & Reffert	2023	0.93	0.20	0.80	875	–	–	–	–
He et al.	2022	1.48	0.25	–	3	-0.881	–	–	–

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

Cluster	%	RA	DEC	Plx	pmRA	pmDE	Rv	UTI
CWNU 25	34.6	133.47	-25.2	1.03	-6.37	2.62	14.46	0.08

💡 Note: The % column shows the percentage of members that CWNU 509 shares with each listed object.

Visualization

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