HSC 2978

0.12 UTI

0.0

C_N

0.17

C_dens

0.38

C_C3

0.03

C_lit

1.0

C_dup

N_m (P>50%) 24

Core radius and density 2.0 [pc], 0.8 [pc^-2]

C3 classification CB

C_N 0.0 Sparse
C_dens 0.17 Very loose
C_C3 0.38 Low 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 2978 is a sparse, very loose object of low C3 quality. Its parallax locates it at a moderate distance, near the mid-plane, affected by high extinction. It is catalogued as a near-solar metallicity, 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.

Relatively close High extinction Near-solar metallicity Very young

Palma et al. (2025)
Classified as optical pair P498, along with UBC_1566.

Cavallo et al. (2024)
Gold sample.

Hunt & Reffert (2024)
Classified as open cluster. CMD class: 0.95 (50th percentile).

Hunt & Reffert (2023)
Classified as open cluster. CMD class: 0.95 (50th percentile).

Data

🔍 Search references for HSC 2978 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–	266.466	-30.296	0.354	-0.298	-2.341	-12.869
Hunt & Reffert	2024	266.486	-30.3	0.354	-0.276	-2.351	-12.871
Cavallo et al.	2024	266.475	-30.288	0.354	–	–	–
Hunt & Reffert	2023	266.486	-30.3	0.354	-0.276	-2.351	-12.871

💡 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–	2.6	4.3	2.67	19	-0.450	590	–	–
Hunt & Reffert	2024	2.60	4.30	2.67	19	–	590⁽¹⁾	–	–
Cavallo et al.	2024	1.95	4.58	–	32	-0.450	–	–	–
Hunt & Reffert	2023	2.60	4.30	2.67	19	–	–	–	–

(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 4284	100.0	266.49	-30.29	0.37	-0.3	-2.34	0.63	0.13

💡 Note: The % column shows the percentage of members that HSC 2978 shares with each listed object.

Visualization

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