Theia 863

0.55 UTI

0.64

C_N

1.0

C_dens

0.5

C_C3

0.3

C_lit

1.0

C_dup

N₅₀ (P>50% members) 77

Stellar density (N₅₀/rad) 6.2 [N/pc²]

C3 classification BB

C_N 0.64 Moderately populated
C_dens 1.0 Very dense
C_C3 0.5 Intermediate quality
C_lit 0.3 Poorly studied
C_dup 1.0 Unique

📥 Members 📊 Colab 🔬 Bayestar19

MOCA 🔍 CDS 🔍 Simbad 🔍 CDS (α, δ) 🔍 Simbad (α, δ)

Overview

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Theia 863 is a moderately populated, very dense object of intermediate 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, but with a large variance across recent sources for the absorption and metallicity parameters (see Parameters). It was recently reported in the literature.

Close Moderate extinction Near-solar metallicity Intermediate age

Liu et al. (2025)
Classified as hyperbolic encounter pair 352 along with Trumpler_2.

Palma et al. (2025)
Part of multiple system G250, along with Theia_1432, Theia_862 and Trumpler_2.

Cavallo et al. (2024)
Gold sample.

Data

🔍 Search references for Theia 863 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–	41.371	56.495	1.4	-0.985	-5.283	-33.231
Zhang et al.	2024	41.406	56.453	–	–	–	–
Hunt & Reffert	2024	41.406	56.453	1.383	-1.03	-5.297	-31.628
Cavallo et al.	2024	41.121	56.514	1.39	–	–	–
Hunt & Reffert	2023	41.406	56.453	1.383	-1.03	-5.297	-31.628

💡 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–	0.75	1.39	1.54	155	0.043	103	–	–
Liu et al.	2025	1.02	0.43	–	93	–	–	–	–
Zhang et al.	2024	–	–	–	–	-0.135⁽¹⁾	–	–	–
Hunt & Reffert	2024	–	–	–	–	–	103⁽¹⁾	–	–
Cavallo et al.	2024	0.75	1.61	–	155	0.220	–	–	–
Hunt & Reffert	2023	0.68	1.39	1.54	165	–	–	–	–

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

Visualization

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