HSC 2870

0.29 UTI

0.0

C_N

0.32

C_dens

1.0

C_C3

0.06

C_lit

1.0

C_dup

N_m (P>50%) 21

Core radius and density 1.2 [pc], 1.6 [pc^-2]

C3 classification AA

C_N 0.0 Sparse
C_dens 0.32 Loose
C_C3 1.0 Very high 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 2870 is a sparse, loose object of very high C3 quality. Its parallax locates it at a moderate distance, near the mid-plane, affected by high extinction. It is catalogued as a metal-poor, very young cluster, but with a large variance across recent sources for the age parameter (see Parameters). It was recently reported in the literature.

Relatively close High extinction Metal-poor Very young

Liu et al. (2025)
Classified as primordial binary cluster 249 along with HSC_2874.

Palma et al. (2025)
Part of multiple system G168, along with OC_0680 and HSC_2874.

Cavallo et al. (2024)
Silver 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 2870 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–	258.627	-39.809	0.385	-0.671	-1.436	–
Hunt & Reffert	2024	258.625	-39.809	0.388	-0.664	-1.429	–
Cavallo et al.	2024	258.643	-39.815	0.388	–	–	–
Hunt & Reffert	2023	258.625	-39.809	0.388	-0.664	-1.429	–

💡 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–	2.68	3.215	2.31	14	-0.710	771	–	–
Liu et al.	2025	6.64	1.09	–	21	–	–	–	–
Hunt & Reffert	2024	2.41	3.26	2.31	8	–	771⁽¹⁾	–	–
Cavallo et al.	2024	2.95	3.17	–	132	-0.710	–	–	–
Hunt & Reffert	2023	2.41	3.26	2.31	8	–	–	–	–

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

Visualization

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