CWNU 1538

0.17 UTI

0.0

C_N

0.23

C_dens

0.5

C_C3

0.06

C_lit

1.0

C_dup

N_m (P>50%) 22

Core radius and density 0.7 [pc], 1.1 [pc^-2]

C3 classification BB

C_N 0.0 Sparse
C_dens 0.23 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 1538 is a sparse, very loose object of intermediate C3 quality. Its parallax locates it at a relatively close distance, near the mid-plane, affected by moderate extinction. It is catalogued as a near-solar metallicity, young cluster (see Parameters). It was recently reported 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 tidal capture (resonant trapping pair) P6, along with CWNU_1529.

Cavallo et al. (2024)
Gold sample.

Hunt & Reffert (2024)
Classified as open cluster. CMD class: 1.00 (50th percentile).

Hunt & Reffert (2023)
Classified as open cluster. CMD class: 1.00 (50th percentile).

Data

🔍 Search references for CWNU 1538 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–	249.039	-49.171	0.595	-1.604	-4.553	-52.274
Hunt & Reffert	2024	249.028	-49.14	0.591	-1.6	-4.549	-52.398
Cavallo et al.	2024	248.952	-49.187	0.592	–	–	–
Hunt & Reffert	2023	249.028	-49.14	0.591	-1.6	-4.549	-52.398
He et al.	2023	248.98	-49.18	0.597	-1.591	-4.55	–

💡 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–	1.595	2.62	0.46	69	0.090	215	–	–
Hunt & Reffert	2024	1.61	2.57	0.46	82	–	215⁽¹⁾	–	–
Cavallo et al.	2024	1.51	2.67	–	56	0.090	–	–	–
Hunt & Reffert	2023	1.61	2.57	0.46	82	–	–	–	–
He et al.	2023	1.58	2.90	–	13	–	–	–	–

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

Visualization

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