Theia 311

0.07 UTI

0.0

C_N

0.02

C_dens

0.25

C_C3

0.03

C_lit

1.0

C_dup

N_m (P>50%) 24

Core radius and density 2.4 [pc], 0.1 [pc^-2]

C3 classification CC

C_N 0.0 Sparse
C_dens 0.02 Very loose
C_C3 0.25 Low quality
C_lit 0.03 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 311 is a sparse, very loose object of low C3 quality. Its parallax locates it at a close distance, near the mid-plane, affected by moderate extinction. It is catalogued as a near-solar metallicity, intermediate-age cluster (see Parameters). It is rarely studied 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 Moderate extinction Near-solar metallicity Intermediate age

Palma et al. (2025)
Classified as optical pair (not dynamically associated) P174, along with Theia_638.

Cavallo et al. (2024)
Gold sample.

Hunt & Reffert (2024)
Classified as moving group. CMD class: 0.40 (50th percentile).

Hunt & Reffert (2023)
Classified as open cluster. CMD class: 0.40 (50th percentile).

Data

🔍 Search references for Theia 311 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–	44.081	61.342	1.815	-0.778	-8.945	-7.39
Cavallo et al.	2024	42.88	59.809	1.783	–	–	–
Hunt & Reffert	2023	44.889	61.204	1.78	-0.703	-9.022	-6.174
Kounkel & Covey	2019	50.973	64.869	3.421	–	–	-6.229

💡 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–	0.54	1.28	1.84	175	0.060	–	–	–
Cavallo et al.	2024	0.55	1.28	–	204	0.060	–	–	–
Hunt & Reffert	2023	0.54	1.29	1.84	175	–	–	–	–
Kounkel & Covey	2019	0.28	0.34	–	107	–	–	–	–

Visualization

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