FSR 0665

0.43 UTI

0.76

C_N

0.44

C_dens

0.5

C_C3

0.23

C_lit

1.0

C_dup

N_m (P>50%) 116

Core radius and density 1.6 [pc], 2.2 [pc^-2]

C3 classification BB

C_N 0.76 Rich
C_dens 0.44 Loose
C_C3 0.5 Intermediate quality
C_lit 0.23 Rarely studied
C_dup 1.0 Unique

📥 Members 📊 Colab 🔬 Bayestar19

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

Overview

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FSR 0665 is a rich, loose object of intermediate 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, young cluster, but with a large variance across recent sources for the metallicity parameter (see Parameters). It is rarely studied in the literature.

Note: This object shares a significant percentage of members with 3 later reported entries. See table with shared members information.

Relatively close High extinction Massive Near-solar metallicity Young

Palma et al. (2025)
Classified as optical pair (not dynamically associated) P307, along with CWNU_1422.

Cavallo et al. (2024)
Silver sample.

Hunt & Reffert (2024)
Classified as open cluster. CMD class: 0.08 (50th percentile).

Hunt & Reffert (2023)
Classified as open cluster. CMD class: 0.08 (50th percentile).

Data

🔍 Search references for FSR 0665 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–	61.318	51.515	0.324	-0.394	-1.263	-8.197
Yang et al.	2025	61.301	51.515	–	–	–	–
Hunt & Reffert	2024	61.301	51.515	0.329	-0.375	-1.25	-37.039
Cavallo et al.	2024	61.374	51.551	0.33	–	–	–
Hunt & Reffert	2023	61.301	51.515	0.329	-0.375	-1.25	-37.039
Monteiro & Dias	2019	61.3	51.522	–	-0.408	-1.189	2.885
Dias et al.	2018	–	–	–	2.39	-2.65	–
Sampedro et al.	2017	61.3	51.522	–	-1.1	1.61	–
Froebrich et al.	2007	61.3	51.522	–	–	–	–
Dias et al.	2002	61.3	51.522	–	1.01	1.52	–

💡 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–	2.95	3.07	2.8	55	0.028	1280	–	–
Yang et al.	2025	–	–	–	55	-0.380⁽³⁾	–	–	–
Hunt & Reffert	2024	2.72	3.25	2.80	55	–	1280⁽¹⁾	–	–
Cavallo et al.	2024	3.18	2.89	–	117	0.330	–	–	–
Hunt & Reffert	2023	2.72	3.25	2.80	55	–	–	–	–
Monteiro & Dias	2019	3.34	2.15	–	88	0.028	–	–	–

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

Cluster	%	RA	DEC	Plx	pmRA	pmDE	Rv	UTI
FSR 0666	75.0	61.36	51.5	0.32	-0.36	-1.29	-12.61	0.06
UBC 1256	73.3	61.33	51.5	0.33	-0.37	-1.29	-12.61	0.0
BDSB 63	4.3	61.74	51.45	0.31	-0.31	-1.29	-12.61	0.04

💡 Note: The % column shows the percentage of members that FSR 0665 shares with each listed object.

Visualization

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