Theia 153

0.14 UTI

0.33

C_N

0.14

C_dens

0.12

C_C3

0.06

C_lit

1.0

C_dup

N_m (P>50%) 33

Core radius and density 2.1 [pc], 0.7 [pc^-2]

C3 classification DC

C_N 0.33 Poorly populated
C_dens 0.14 Very loose
C_C3 0.12 Very low 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 153 is a poorly populated, very loose object of very low 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, 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 Moderate extinction Near-solar metallicity Young

Palma et al. (2025)
Part of multiple system G199, along with HSC_900, Theia_775 and HSC_922.

Cavallo et al. (2024)
Gold sample.

Hunt & Reffert (2024)
Classified as open cluster. CMD class: 0.83 (50th percentile).

Hunt & Reffert (2023)
Classified as open cluster. CMD class: 0.83 (50th percentile).

Data

🔍 Search references for Theia 153 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–	355.941	60.167	1.184	-1.59	-1.928	-7.894
Hunt & Reffert	2024	355.942	60.133	1.177	-1.581	-1.944	-7.819
Cavallo et al.	2024	356.206	60.246	1.181	–	–	–
Hunt & Reffert	2023	355.942	60.133	1.177	-1.581	-1.944	-7.819
Kounkel & Covey	2019	357.066	60.428	1.163	–	–	4.182

💡 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–	0.825	1.67	2.07	34	0.030	79	–	–
Hunt & Reffert	2024	0.81	1.67	2.07	34	–	79⁽¹⁾	–	–
Cavallo et al.	2024	0.90	1.89	–	24	0.030	–	–	–
Hunt & Reffert	2023	0.81	1.67	2.07	34	–	–	–	–
Kounkel & Covey	2019	0.84	1.11	–	56	–	–	–	–

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

Visualization

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