Theia 23

0.60 UTI

0.76

C_N

1.0

C_dens

1.0

C_C3

0.13

C_lit

1.0

C_dup

N_m (P>50%) 115

Core radius and density 1.2 [pc], 6.6 [pc^-2]

C3 classification AA

C_N 0.76 Rich
C_dens 1.0 Very dense
C_C3 1.0 Very high quality
C_lit 0.13 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 23 is a rich, very dense object of very high C3 quality. Its parallax locates it at a very close distance, near the mid-plane, affected by moderate extinction. It is catalogued as a near-solar metallicity, young cluster, but with a large variance across recent sources for the absorption parameter (see Parameters). It is rarely studied in the literature.

Note: This object shares a large percentage of members with 3 later reported entries. See table with shared members information.

Very close Moderate extinction Near-solar metallicity Young

Liu et al. (2025)
Classified as tidal capture (resonant trapping binary) 165 along with HSC_238.

Palma et al. (2025)
Classified as tidal capture (resonant trapping pair) P40, along with HSC_238.

Cavallo et al. (2024)
Gold sample.

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

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

Data

🔍 Search references for Theia 23 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–	277.896	-3.947	2.605	2.077	-8.995	-8.258
Swiggum et al.	2024	277.938	-3.925	2.601	2.068	-9.001	-8.002
Hunt & Reffert	2024	277.938	-3.925	2.601	2.068	-9.001	-9.59
Cavallo et al.	2024	277.92	-3.922	2.61	–	–	–
Hunt & Reffert	2023	277.938	-3.925	2.601	2.068	-9.001	-9.59
Kounkel & Covey	2019	278.228	-2.939	2.295	–	–	6.608

💡 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–	0.385	2.53	2.45	21	0.240	266	–	–
Liu et al.	2025	0.41	0.48	–	72	–	–	–	–
Swiggum et al.	2024	0.38	–	–	21	–	327	–	–
Hunt & Reffert	2024	0.37	2.75	2.45	21	–	205⁽¹⁾	–	–
Cavallo et al.	2024	0.39	2.53	–	15	0.240	–	–	–
Hunt & Reffert	2023	0.37	2.75	2.45	21	–	–	–	–
Kounkel & Covey	2019	0.49	1.37	–	12	–	–	–	–

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

Cluster	%	RA	DEC	Plx	pmRA	pmDE	Rv	UTI
OCSN 247	100.0	277.89	-3.95	2.6	2.01	-9.02	-8.03	0.01
PHOC 39	100.0	277.88	-3.95	2.57	2.0	-8.98	-7.34	0.31
CWWL 3567	63.5	277.91	-3.91	2.61	2.06	-9.03	-7.18	0.0

💡 Note: The % column shows the percentage of members that Theia 23 shares with each listed object.

Visualization

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