UPK 645

0.72 UTI

0.5

C_N

1.0

C_dens

1.0

C_C3

0.55

C_lit

1.0

C_dup

N₅₀ (P>50% members) 51

Stellar density (N₅₀/rad) 15.8 [N/pc²]

C3 classification AA

C_N 0.5 Moderately populated
C_dens 1.0 Very dense
C_C3 1.0 Very high quality
C_lit 0.55 Moderately studied
C_dup 1.0 Unique

📥 Members 📊 Colab 🔬 Bayestar19

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

Overview

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UPK 645 is a moderately populated, very dense object of very high C3 quality. Its parallax locates it at a close distance, below the mid-plane, affected by low extinction. It is catalogued as a near-solar metallicity, intermediate-age cluster, but with a large variance across recent sources for the age and metallicity parameters (see Parameters). It is moderately studied in the literature.

Close Low extinction Near-solar metallicity Intermediate age

Palma et al. (2025)
Classified as optical pair (not dynamically associated) P153, along with HSC_2865.

Cavallo et al. (2024)
Gold sample.

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

Hunt & Reffert (2024)
Classified as open cluster. CMD class: 0.97 (50th percentile).

Data

🔍 Search references for UPK 645 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–	270.129	-42.787	1.427	2.746	-2.887	-3.256
Li et al.	2025	270.167	-42.783	1.43	2.797	-2.844	–
Almeida et al.	2025	270.129	-42.708	–	–	–	–
Alfonso et al.	2024	270.179	-42.767	1.38	2.735	-2.888	–
Hunt & Reffert	2024	270.14	-42.84	1.41	2.76	-2.893	-0.245
Cavallo et al.	2024	270.146	-42.69	1.41	–	–	–
Hunt & Reffert	2023	270.14	-42.84	1.41	2.76	-2.893	-0.245
He et al.	2022	270.175	-42.785	1.403	2.751	-2.924	–
Tarricq et al.	2022	270.182	-42.794	1.442	2.771	-2.887	–
Dias et al.	2021	270.129	-42.708	1.432	2.772	-2.847	2.807
Cantat-Gaudin et al.	2020	270.167	-42.783	1.43	2.797	-2.844	–
Cantat-Gaudin & Anders	2020	270.167	-42.739	1.426	2.773	-2.843	–
Sim et al.	2019	270.177	-42.733	–	2.76	-2.85	–

💡 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–	0.69	0.335	0.63	138	-0.007	138	–	–
Li et al.	2025	0.71	0.17	–	501	0.131	–	–	–
Almeida et al.	2025	0.69	0.32	–	466	–	136	–	–
Alfonso et al.	2024	0.70	0.35	–	365	-0.007	–	–	–
Hunt & Reffert	2024	–	–	–	–	–	140⁽¹⁾	–	–
Cavallo et al.	2024	0.67	0.71	–	105	-0.290	–	–	–
Hunt & Reffert	2023	0.67	0.19	0.63	160	–	–	–	–
He et al.	2022	–	0.60	–	50	–	–	–	–
Tarricq et al.	2022	0.68	–	–	115	–	–	–	–
Dias et al.	2021	0.69	0.32	–	466	-0.007	–	–	–
Cantat-Gaudin et al.	2020	0.70	0.35	–	105	–	–	–	–
Cantat-Gaudin & Anders	2020	0.69	–	–	–	–	–	–	–
Sim et al.	2019	0.68	–	–	89	–	–	–	–

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

Visualization

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