OC 0640

0.00 UTI

0.64

C_N

1.0

C_dens

1.0

C_C3

0.1

C_lit

0.0

C_dup

N_m (P>50%) 77

Core radius and density 0.6 [pc], 15 [pc^-2]

C3 classification AA

C_N 0.64 Moderately populated
C_dens 1.0 Very dense
C_C3 1.0 Very high quality
C_lit 0.1 Rarely studied
C_dup 0.0 Very likely duplicate

📥 Members 📊 Colab 🔬 Bayestar19

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

Overview

ℹ️

OC 0640 is a moderately populated, very dense 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 massive, near-solar metallicity, intermediate-age cluster, but with a large variance across recent sources for the metallicity parameter (see Parameters). It is rarely studied in the literature.

⚠️ Warning: This is very likely a duplicate object, which shares a large percentage of members with at least one previously reported entry, and a moderate percentage with at least one entry reported in the same catalogue. See table with shared members information.

Relatively close High extinction Massive Near-solar metallicity Intermediate age

Cavallo et al. (2024)
Gold sample.

Hunt & Reffert (2024)
Classified as open cluster. CMD class: 0.32 (50th percentile).

Hunt & Reffert (2023)
Classified as open cluster. CMD class: 0.32 (50th percentile).

Data

🔍 Search references for OC 0640 in: SciX Simbad

ℹ️

Reference	Year	RA [deg]	DEC [deg]	Plx [mas]	pmRA [mas/yr]	pmDE [mas/yr]	Rv [km/s]
UCC	99999–	240.407	-52.111	0.417	-4.93	-5.416	-39.316
Hu & Soubiran	2025	240.416	-52.126	–	–	–	–
Hunt & Reffert	2024	240.416	-52.111	0.439	-4.907	-5.418	-35.933
Cavallo et al.	2024	240.415	-52.126	0.44	–	–	–
Hunt & Reffert	2023	240.416	-52.111	0.439	-4.907	-5.418	-35.933
Hao et al.	2022	240.415	-52.116	0.425	-4.921	-5.422	–

💡 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–	2.14	3.75	2.4	980	-0.250	1934	–	–
Hu & Soubiran	2025	–	–	–	–	-0.270⁽⁵⁾	–	–	–
Hunt & Reffert	2024	2.14	3.75	2.40	701	–	1934⁽¹⁾	–	–
Cavallo et al.	2024	1.71	3.59	–	1698	-0.250	–	–	–
Hunt & Reffert	2023	2.14	3.75	2.40	701	–	–	–	–
Hao et al.	2022	–	4.84	–	1259	0.265	–	–	–

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

Cluster	%	RA	DEC	Plx	pmRA	pmDE	Rv	UTI
FoF 434	100.0	240.42	-52.12	0.43	-4.92	-5.42	-37.26	0.56
OC 0641	39.0	240.43	-52.11	0.46	-4.96	-5.41	-40.22	0.0

💡 Note: The % column shows the percentage of members that OC 0640 shares with each listed object.

Visualization

ℹ️

1 2