UBC 40

0.34 UTI

0.33

C_N

0.37

C_dens

0.5

C_C3

0.26

C_lit

1.0

C_dup

N_m (P>50%) 33

Core radius and density 1.6 [pc], 1.9 [pc^-2]

C3 classification BB

C_N 0.33 Poorly populated
C_dens 0.37 Loose
C_C3 0.5 Intermediate quality
C_lit 0.26 Poorly studied
C_dup 1.0 Unique

📥 Members 📊 Colab 🔬 Bayestar19

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

Overview

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UBC 40 is a poorly populated, loose object of intermediate C3 quality. Its parallax locates it at a moderate distance, below 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 age parameters (see Parameters). It is poorly studied in the literature.

Relatively close Moderate extinction Near-solar metallicity Intermediate age

Liu et al. (2025)
Classified as primordial binary cluster 372 along with UBC_41.

Palma et al. (2025)
Classified as optical pair P604, along with UBC_41.

Almeida et al. (2025)
Mass determination: good fit. Isochrone match: good fit. Silver sample.

Cavallo et al. (2024)
Gold sample.

Hunt & Reffert (2024)
Classified as open cluster. CMD class: 1.00 (50th percentile).

Hunt & Reffert (2023)
Classified as open cluster. CMD class: 1.00 (50th percentile).

Hu et al. (2021)
Ellipticities (core, all): e_core=0.2589, e_all=0.2445.

Data

🔍 Search references for UBC 40 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–	22.643	60.243	0.412	-1.087	-0.611	–
Almeida et al.	2025	22.633	60.244	–	–	–	–
Hunt & Reffert	2024	22.63	60.238	0.416	-1.087	-0.641	–
Cavallo et al.	2024	22.59	60.246	0.416	–	–	–
Hunt & Reffert	2023	22.63	60.238	0.416	-1.087	-0.641	–
Dias et al.	2021	22.633	60.244	0.363	-1.061	-0.614	–
Cantat-Gaudin et al.	2020	22.643	60.245	0.402	-1.082	-0.556	–
Cantat-Gaudin & Anders	2020	22.643	60.245	0.402	-1.082	-0.556	–
Castro-Ginard et al.	2019	22.629	60.236	0.402	-1.014	-0.564	–

💡 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–	2.32	1.155	0.5	109	-0.088	230	–	–
Liu et al.	2025	2.87	0.34	–	155	–	–	–	–
Almeida et al.	2025	2.23	1.38	–	109	–	344	–	–
Hunt & Reffert	2024	2.32	1.03	0.50	241	–	115⁽¹⁾	–	–
Cavallo et al.	2024	2.68	1.66	–	44	0.050	–	–	–
Hunt & Reffert	2023	2.32	1.03	0.50	242	–	–	–	–
Dias et al.	2021	2.23	1.38	–	109	-0.226	–	–	–
Cantat-Gaudin et al.	2020	2.45	1.03	–	79	–	–	–	–
Kounkel et al.	2020	2.47	1.28	–	50	–	–	–	–
Cantat-Gaudin & Anders	2020	2.32	–	–	–	–	–	–	–

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

Visualization

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