Theia 283

0.13 UTI

0.0

C_N

0.11

C_dens

0.12

C_C3

0.25

C_lit

0.88

C_dup

N₅₀ (P>50% members) 24

Stellar density (N₅₀/rad) 0.6 [N/pc²]

C3 classification DC

C_N 0.0 Sparse
C_dens 0.11 Very loose
C_C3 0.12 Very low quality
C_lit 0.25 Poorly studied
C_dup 0.88 Very likely unique

📥 Members 📊 Colab 🔬 Bayestar19

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

Overview

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Theia 283 is a sparse, very loose object of very low C3 quality. Its parallax locates it at a relatively close distance, near the mid-plane, affected by low extinction. It is catalogued as a near-solar metallicity, intermediate-age cluster (see Parameters). It was recently reported in the literature.

Note: This is very likely a unique object, which shares a small percentage of members with at least one previously reported entry. See table with shared members information.

⚠️ Warning: the low UTI value and no obvious signs of duplication (C_dup=0.88) indicate that this is quite probably an asterism, moving group, or artifact, and not a real open cluster.

Relatively close Low extinction Near-solar metallicity Intermediate age

Liu et al. (2025)
Classified as tidal capture (resonant trapping binary) 350 along with UPK_470.

Palma et al. (2025)
Part of multiple system G242, along with ASCC_36 and UPK_470.

Cavallo et al. (2024)
Gold sample.

Data

🔍 Search references for Theia 283 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–	109.042	-18.495	0.98	-3.399	4.049	8.959
Hunt & Reffert	2024	108.943	-18.58	0.948	-3.368	3.993	24.27
Cavallo et al.	2024	109.199	-18.659	0.951	–	–	–
Hunt & Reffert	2023	108.943	-18.58	0.948	-3.368	3.993	24.27

💡 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–	1.04	0.21	0.78	158	-0.300	70	–	–
Liu et al.	2025	1.37	0.17	–	66	–	–	–	–
Hunt & Reffert	2024	–	–	–	–	–	70⁽¹⁾	–	–
Cavallo et al.	2024	1.04	0.81	–	158	-0.300	–	–	–
Hunt & Reffert	2023	0.99	0.21	0.78	186	–	–	–	–

(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 8	12.0	109.16	-18.98	1.04	-3.67	4.25	23.28	0.13

💡 Note: The % column shows the percentage of members that Theia 283 shares with each listed object.

Visualization

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