HSC 1643

0.17 UTI

0.28

C_N

0.04

C_dens

0.38

C_C3

0.06

C_lit

1.0

C_dup

N_m (P>50%) 28

Core radius and density 4.0 [pc], 0.2 [pc^-2]

C3 classification CB

C_N 0.28 Poorly populated
C_dens 0.04 Very loose
C_C3 0.38 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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HSC 1643 is a poorly populated, very loose object of low C3 quality. Its parallax locates it at a large distance, above the mid-plane, affected by moderate extinction. It is catalogued as a near-solar metallicity, intermediate-age cluster (see Parameters). It was recently reported in the literature.

Note: This object shares a large percentage of members with a later reported entry. See table with shared members information.

⚠️ 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.

Distant Moderate extinction Near-solar metallicity Intermediate age

Cavallo et al. (2024)
Gold sample.

Hunt & Reffert (2024)
Classified as open cluster. CMD class: 0.09 (50th percentile).

Hunt & Reffert (2023)
Classified as open cluster. CMD class: 0.09 (50th percentile).

Data

🔍 Search references for HSC 1643 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–	103.225	5.455	0.161	-0.008	-0.841	72.698
Hu & Soubiran	2025	103.219	5.443	–	–	–	–
Hunt & Reffert	2024	103.217	5.438	0.164	-0.009	-0.823	72.222
Cavallo et al.	2024	103.219	5.443	0.164	–	–	–
Hunt & Reffert	2023	103.217	5.438	0.164	-0.009	-0.823	72.222

💡 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–	4.55	1.55	2.13	570	-0.240	296	–	–
Hu & Soubiran	2025	–	–	–	–	-0.290⁽⁵⁾	–	–	–
Hunt & Reffert	2024	4.55	1.55	2.13	570	–	296⁽¹⁾	–	–
Cavallo et al.	2024	4.43	1.21	–	1380	-0.190	–	–	–
Hunt & Reffert	2023	4.55	1.55	2.13	570	–	–	–	–

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

Cluster	%	RA	DEC	Plx	pmRA	pmDE	Rv	UTI
CWNU 3204	100.0	103.23	5.46	0.17	-0.01	-0.82	70.77	0.09

💡 Note: The % column shows the percentage of members that HSC 1643 shares with each listed object.

Visualization

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