Theia 118

0.23 UTI

0.27

C_N

0.49

C_dens

0.38

C_C3

0.0

C_lit

1.0

C_dup

N₅₀ (P>50% members) 27

Stellar density (N₅₀/rad) 2.4 [N/pc²]

C3 classification CB

C_N 0.27 Poorly populated
C_dens 0.49 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

ℹ️

Theia 118 is a poorly populated, loose object of low C3 quality. Its parallax locates it at a very close distance, near the mid-plane, affected by low extinction. It is catalogued as a near-solar metallicity, young cluster, but with a large variance across recent sources for the age 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.

Very close Low extinction Near-solar metallicity Young

Liu et al. (2025)
Classified as primordial binary cluster 212 along with HSC_1849, and of multiple system 59 along with HSC_1849 and HSC_1840.

Palma et al. (2025)
Classified as tidal capture (resonant trapping pair) P616, along with HSC_1849.

Cavallo et al. (2024)
Gold sample.

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

Data

🔍 Search references for Theia 118 in: SciX Simbad

ℹ️

Reference	Year	RA [deg]	DEC [deg]	Plx [mas]	pmRA [mas/yr]	pmDE [mas/yr]	Rv [km/s]
UCC	99999–	111.997	-25.466	3.853	-14.286	8.873	29.04
Liu et al.	2025	111.81	-25.39	3.86	-14.33	8.69	29.56
Cavallo et al.	2024	112.181	-25.441	3.874	–	–	–
Hunt & Reffert	2023	111.805	-25.392	3.863	-14.326	8.694	29.562

💡 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–	0.25	0.2	0.36	32	0.000	–	–	–
Liu et al.	2025	0.34	0.10	–	32	–	–	–	–
Cavallo et al.	2024	0.25	0.26	–	20	0.000	–	–	–
Hunt & Reffert	2023	0.25	0.20	0.36	1897	–	–	–	–

Visualization

ℹ️

1 2