Theia 256

0.16 UTI

0.25

C_N

0.19

C_dens

0.38

C_C3

0.0

C_lit

1.0

C_dup

N₅₀ (P>50% members) 25

Stellar density (N₅₀/rad) 0.9 [N/pc²]

C3 classification CB

C_N 0.25 Poorly populated
C_dens 0.19 Very loose
C_C3 0.38 Low quality
C_lit 0.0 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 256 is a poorly populated, very loose object of low 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 metallicity parameter (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.

Close Low extinction Near-solar metallicity Intermediate age

Cavallo et al. (2024)
Gold sample.

Hunt & Reffert (2024)
Classified as a moving group.

Data

🔍 Search references for Theia 256 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–	123.788	7.189	1.821	-8.191	-1.281	18.11
Zhang et al.	2024	123.759	7.061	–	–	–	–
Cavallo et al.	2024	123.773	7.268	1.811	–	–	–
Hunt & Reffert	2023	123.759	7.061	1.814	-8.13	-1.303	30.697

💡 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–	0.545	0.065	0.37	108	0.088	–	–	–
Zhang et al.	2024	–	–	–	–	-0.104⁽¹⁾	–	–	–
Cavallo et al.	2024	0.56	0.08	–	129	0.280	–	–	–
Hunt & Reffert	2023	0.53	0.05	0.37	88	–	–	–	–

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

Visualization

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