Theia 546

0.22 UTI

0.34

C_N

0.09

C_dens

0.5

C_C3

0.1

C_lit

1.0

C_dup

N_m (P>50%) 34

Core radius and density 3.3 [pc], 0.4 [pc^-2]

C3 classification BB

C_N 0.34 Poorly populated
C_dens 0.09 Very loose
C_C3 0.5 Intermediate quality
C_lit 0.1 Rarely studied
C_dup 1.0 Unique

📥 Members 📊 Colab 🔬 Bayestar19

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

Overview

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Theia 546 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 (see Parameters). It is rarely studied in the literature.

Note: This object shares a significant percentage of members with a later reported entry. 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

Palma et al. (2025)
Classified as optical pair P571, along with Theia_128.

Cavallo et al. (2024)
Gold sample.

Hunt & Reffert (2024)
Classified as open cluster. CMD class: 0.91 (50th percentile).

Hunt & Reffert (2023)
Classified as open cluster. CMD class: 0.91 (50th percentile).

Data

🔍 Search references for Theia 546 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–	110.191	-4.303	1.908	-2.152	-3.689	8.192
Zhang et al.	2024	110.172	-4.38	–	–	–	–
Hunt & Reffert	2024	110.172	-4.38	1.91	-2.136	-3.711	8.379
Cavallo et al.	2024	110.415	-4.091	1.904	–	–	–
Hunt & Reffert	2023	110.172	-4.38	1.91	-2.136	-3.711	8.379
Kounkel & Covey	2019	110.072	-4.797	1.762	–	–	-9.954

💡 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–	0.52	0.165	0.67	258	-0.047	77	–	–
Zhang et al.	2024	–	–	–	–	-0.154⁽¹⁾	–	–	–
Hunt & Reffert	2024	0.50	0.10	0.67	292	–	77⁽¹⁾	–	–
Cavallo et al.	2024	0.54	0.28	–	100	0.060	–	–	–
Hunt & Reffert	2023	0.50	0.10	0.67	292	–	–	–	–
Kounkel & Covey	2019	0.57	0.23	–	225	–	–	–	–

(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 100	67.6	110.4	-4.3	1.89	-2.15	-3.63	8.4	0.05

💡 Note: The % column shows the percentage of members that Theia 546 shares with each listed object.

Visualization

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