HSC 1820

0.10 UTI

0.0

C_N

0.05

C_dens

0.5

C_C3

0.03

C_lit

0.84

C_dup

N_m (P>50%) 16

Core radius and density 2.5 [pc], 0.2 [pc^-2]

C3 classification BB

C_N 0.0 Sparse
C_dens 0.05 Very loose
C_C3 0.5 Intermediate quality
C_lit 0.03 Rarely studied
C_dup 0.84 Very likely unique

📥 Members 📊 Colab 🔬 Bayestar19

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

Overview

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HSC 1820 is a sparse, very loose object of intermediate 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, young cluster (see Parameters). It was recently reported in the literature.

Note: This is very likely a unique object, which shares a small percentage of members with at least one previously reported entry. See table with shared members information.

⚠️ Warning: the low UTI value and no obvious signs of duplication (C_dup=0.84) indicate that this is quite probably an asterism, moving group, or artifact, and not a real open cluster.

Distant Moderate extinction Near-solar metallicity Young

Cavallo et al. (2024)
Gold sample.

Hunt & Reffert (2024)
Classified as open cluster. CMD classes: 0.99 (50th percentile), true positive? (human-assigned).

Hunt & Reffert (2023)
Classified as open cluster. CMD classes: 0.99 (50th percentile), true positive? (human-assigned).

Data

🔍 Search references for HSC 1820 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–	111.979	-15.399	0.172	-1.512	1.468	–
Hunt & Reffert	2024	111.981	-15.38	0.169	-1.526	1.45	–
Cavallo et al.	2024	111.951	-15.411	0.17	–	–	–
Hunt & Reffert	2023	111.981	-15.38	0.169	-1.526	1.45	–

💡 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–	4.67	2.15	1.21	55	0.070	268	–	–
Hunt & Reffert	2024	4.67	2.15	1.21	55	–	268⁽¹⁾	–	–
Cavallo et al.	2024	3.72	2.14	–	93	0.070	–	–	–
Hunt & Reffert	2023	4.67	2.15	1.21	55	–	–	–	–

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

Cluster	%	RA	DEC	Plx	pmRA	pmDE	Rv	UTI
Haffner 10	16.0	112.15	-15.36	0.26	-1.18	1.57	87.99	0.88
Czernik 29	8.0	112.11	-15.4	0.24	-1.55	1.32	88.41	0.45

💡 Note: The % column shows the percentage of members that HSC 1820 shares with each listed object.

Visualization

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