Theia 900

0.28 UTI

0.31

C_N

0.12

C_dens

0.62

C_C3

0.16

C_lit

1.0

C_dup

N_m (P>50%) 31

Core radius and density 1.0 [pc], 0.6 [pc^-2]

C3 classification AC

C_N 0.31 Poorly populated
C_dens 0.12 Very loose
C_C3 0.62 Intermediate quality
C_lit 0.16 Rarely studied
C_dup 1.0 Unique

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

Overview

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Theia 900 is a poorly populated, very loose 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 (see Parameters). It is rarely studied in the literature.

Close Moderate extinction Near-solar metallicity Intermediate age

Cavallo et al. (2024)
Gold sample.

Hunt & Reffert (2024)
Classified as open cluster. CMD class: 0.98 (50th percentile).

Hunt & Reffert (2023)
Classified as open cluster. CMD class: 0.98 (50th percentile).

Data

🔍 Search references for Theia 900 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–	37.306	59.141	1.108	3.578	-2.873	-8.135
Hu & Soubiran	2025	37.288	59.094	–	–	–	–
Yang et al.	2025	37.625	59.052	–	–	–	–
Hunt & Reffert	2024	37.625	59.052	1.109	3.563	-2.874	-10.189
Cavallo et al.	2024	37.288	59.094	1.118	–	–	–
Hunt & Reffert	2023	37.625	59.052	1.109	3.563	-2.874	-10.189
He et al.	2022	37.237	59.308	1.106	3.539	-2.826	–
Kounkel & Covey	2019	37.538	58.889	1.127	–	–	-7.808

💡 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–	0.85	1.48	1.55	333	-0.090	93	–	–
Hu & Soubiran	2025	–	–	–	–	-0.080⁽⁵⁾	–	–	–
Yang et al.	2025	–	–	–	331	-0.090⁽³⁾	–	–	–
Hunt & Reffert	2024	0.85	1.48	1.55	333	–	93⁽¹⁾	–	–
Cavallo et al.	2024	0.85	1.71	–	537	-0.100	–	–	–
Hunt & Reffert	2023	0.85	1.48	1.55	333	–	–	–	–
He et al.	2022	–	2.10	–	282	–	–	–	–
Kounkel & Covey	2019	0.89	1.37	–	419	–	–	–	–

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

Visualization

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