Theia 2166

0.05 UTI

0.28

C_N

0.86

C_dens

0.75

C_C3

0.3

C_lit

0.11

C_dup

N₅₀ (P>50% members) 28

Stellar density (N₅₀/rad) 4.3 [N/pc²]

C3 classification BA

C_N 0.28 Poorly populated
C_dens 0.86 Dense
C_C3 0.75 High quality
C_lit 0.3 Poorly studied
C_dup 0.11 Likely duplicate

📥 Members 📊 Colab 🔬 Bayestar19

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

Overview

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Theia 2166 is a poorly populated, dense object of high 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, intermediate-age cluster, but with a large variance across recent sources for the distance parameter (see Parameters). It was recently reported in the literature.

⚠️ Warning: This is likely a duplicate object, which shares a large percentage of members with at least one previously reported entry. See table with shared members information.

Relatively close Moderate extinction Near-solar metallicity Intermediate age

Liu et al. (2025)
Classified as tidal capture (resonant trapping binary) 69 along with CWNU_356.

Palma et al. (2025)
Classified as optical pair P574, along with Theia_3274.

Cavallo et al. (2024)
Gold sample.

Data

🔍 Search references for Theia 2166 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–	217.025	-61.352	0.572	-4.395	-1.923	-39.935
Hu & Soubiran	2025	217.086	-61.359	–	–	–	–
Hunt & Reffert	2024	216.985	-61.364	0.57	-4.443	-1.948	-40.28
Cavallo et al.	2024	217.086	-61.36	0.571	–	–	–
Hunt & Reffert	2023	216.985	-61.364	0.57	-4.443	-1.948	-40.28

💡 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–	1.66	1.58	0.64	700	-0.285	161	–	–
Liu et al.	2025	5.92	0.84	–	288	–	–	–	–
Hu & Soubiran	2025	–	–	–	–	-0.270⁽⁵⁾	–	–	–
Hunt & Reffert	2024	–	–	–	–	–	161⁽¹⁾	–	–
Cavallo et al.	2024	1.45	1.72	–	891	-0.300	–	–	–
Hunt & Reffert	2023	1.66	1.58	0.64	700	–	–	–	–

(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 1448	89.3	217.1	-61.35	0.57	-4.39	-1.92	-39.93	0.32

💡 Note: The % column shows the percentage of members that Theia 2166 shares with each listed object.

Visualization

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