HSC 684

0.19 UTI

0.0

C_N

0.1

C_dens

0.38

C_C3

0.25

C_lit

1.0

C_dup

N₅₀ (P>50% members) 17

Stellar density (N₅₀/rad) 0.5 [N/pc²]

C3 classification BC

C_N 0.0 Sparse
C_dens 0.1 Very loose
C_C3 0.38 Low quality
C_lit 0.25 Poorly studied
C_dup 1.0 Unique

📥 Members 📊 Colab 🔬 Bayestar19

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

Overview

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HSC 684 is a sparse, very loose object of low C3 quality. Its parallax locates it at a relatively 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 metallicity parameter (see Parameters). It was recently reported 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.

Relatively close Low extinction Near-solar metallicity Intermediate age

Cavallo et al. (2024)
Gold sample.

Data

🔍 Search references for HSC 684 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–	320.475	42.349	0.567	-0.966	-1.954	–
Hu & Soubiran	2025	320.474	42.431	–	–	–	–
Hunt & Reffert	2024	320.545	42.35	0.572	-0.988	-1.946	–
Cavallo et al.	2024	320.474	42.431	0.576	–	–	–
Hunt & Reffert	2023	320.545	42.35	0.572	-0.988	-1.946	–

💡 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–	1.715	0.865	1.14	494	0.120	54	–	–
Hu & Soubiran	2025	–	–	–	–	-0.090⁽⁵⁾	–	–	–
Hunt & Reffert	2024	–	–	–	–	–	54⁽¹⁾	–	–
Cavallo et al.	2024	1.76	0.75	–	741	0.330	–	–	–
Hunt & Reffert	2023	1.67	0.98	1.14	246	–	–	–	–

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

Visualization

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