Theia 105

0.13 UTI

0.0

C_N

0.02

C_dens

0.5

C_C3

0.06

C_lit

1.0

C_dup

N_m (P>50%) 24

Core radius and density 6.7 [pc], 0.1 [pc^-2]

C3 classification BB

C_N 0.0 Sparse
C_dens 0.02 Very loose
C_C3 0.5 Intermediate quality
C_lit 0.06 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 105 is a sparse, very loose object of intermediate C3 quality. Its parallax locates it at a close distance, near the mid-plane, affected by low extinction. It is catalogued as a near-solar metallicity, young 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 Young

Palma et al. (2025)
Part of multiple system G143, along with HSC_2215, HSC_2126 and HSC_2235.

Cavallo et al. (2024)
Gold sample.

Hunt & Reffert (2024)
Classified as moving group. CMD class: 0.99 (50th percentile).

Hunt & Reffert (2023)
Classified as open cluster. CMD class: 0.99 (50th percentile).

Data

🔍 Search references for Theia 105 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–	139.444	-45.346	1.94	-9.199	0.056	15.304
Swiggum et al.	2024	139.541	-45.847	1.916	-9.225	0.062	13.896
Cavallo et al.	2024	139.602	-45.423	1.936	–	–	–
Hunt & Reffert	2023	139.541	-45.847	1.916	-9.225	0.062	12.543
Kounkel & Covey	2019	139.566	-45.215	1.762	–	–	9.759

💡 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–	0.525	0.23	0.42	21	-0.100	89	–	–
Swiggum et al.	2024	0.51	–	–	21	–	89	–	–
Cavallo et al.	2024	0.54	0.55	–	9	-0.100	–	–	–
Hunt & Reffert	2023	0.51	0.13	0.42	21	–	–	–	–
Kounkel & Covey	2019	0.57	0.23	–	32	–	–	–	–

Visualization

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