Theia 358

0.15 UTI

0.0

C_N

0.05

C_dens

0.62

C_C3

0.03

C_lit

1.0

C_dup

N_m (P>50%) 23

Core radius and density 2.6 [pc], 0.3 [pc^-2]

C3 classification AC

C_N 0.0 Sparse
C_dens 0.05 Very loose
C_C3 0.62 Intermediate 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 358 is a sparse, very loose object of intermediate C3 quality. Its parallax locates it at a close distance, below 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.

⚠️ 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)
Part of multiple system G157, along with HSC_2490, HSC_2499 and HSC_2507.

Cavallo et al. (2024)
Gold sample.

Hunt & Reffert (2024)
Classified as moving group. CMD classes: 1.00 (50th percentile), true positive (human-assigned).

Hunt & Reffert (2023)
Classified as open cluster. CMD classes: 1.00 (50th percentile), true positive (human-assigned).

Data

🔍 Search references for Theia 358 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–	190.529	-69.379	1.042	-4.46	-2.048	2.26
Cavallo et al.	2024	191.3	-69.317	1.038	–	–	–
Hunt & Reffert	2023	190.506	-69.458	1.038	-4.505	-2.095	-2.195
Kounkel & Covey	2019	200.114	-69.574	1.15	–	–	-4.821

💡 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–	0.92	0.49	0.79	121	0.170	–	–	–
Cavallo et al.	2024	0.93	0.49	–	209	0.170	–	–	–
Hunt & Reffert	2023	0.92	0.43	0.79	121	–	–	–	–
Kounkel & Covey	2019	0.88	0.63	–	109	–	–	–	–

Visualization

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