HSC 644

0.19 UTI

0.34

C_N

0.04

C_dens

0.5

C_C3

0.03

C_lit

1.0

C_dup

N_m (P>50%) 34

Core radius and density 2.7 [pc], 0.2 [pc^-2]

C3 classification BB

C_N 0.34 Poorly populated
C_dens 0.04 Very loose
C_C3 0.5 Intermediate quality
C_lit 0.03 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 644 is a poorly populated, very loose object of intermediate C3 quality. Its parallax locates it at a moderate distance, above the mid-plane, affected by very high extinction. It is catalogued as a metal-rich, very young 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 Very high extinction Metal-rich Very young

Palma et al. (2025)
Classified as optical pair P513, along with HSC_652.

Cavallo et al. (2024)
Wood sample.

Hunt & Reffert (2024)
Classified as open cluster. CMD class: 0.86 (50th percentile).

Hunt & Reffert (2023)
Classified as open cluster. CMD class: 0.86 (50th percentile).

Data

🔍 Search references for HSC 644 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–	310.454	43.428	0.275	-2.454	-4.192	-44.139
Hunt & Reffert	2024	310.462	43.399	0.296	-2.459	-4.198	–
Cavallo et al.	2024	310.449	43.453	0.288	–	–	–
Hunt & Reffert	2023	310.462	43.399	0.296	-2.459	-4.198	–

💡 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–	3.16	5.48	2.48	7	0.730	799	–	–
Hunt & Reffert	2024	3.16	5.48	2.48	7	–	799⁽¹⁾	–	–
Cavallo et al.	2024	3.21	4.43	–	20	0.730	–	–	–
Hunt & Reffert	2023	3.16	5.48	2.48	7	–	–	–	–

(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 3888	91.2	310.46	43.45	0.28	-2.45	-4.19	-44.14	0.03

💡 Note: The % column shows the percentage of members that HSC 644 shares with each listed object.

Visualization

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