FSR 1645

(MWSC 2110)

0.20 UTI

0.0

C_N

0.03

C_dens

0.25

C_C3

0.35

C_lit

1.0

C_dup

N_m (P>50%) 22

Core radius and density 2.7 [pc], 0.1 [pc^-2]

C3 classification CC

C_N 0.0 Sparse
C_dens 0.03 Very loose
C_C3 0.25 Low quality
C_lit 0.35 Poorly studied
C_dup 1.0 Unique

📥 Members 📊 Colab 🔬 Bayestar19

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

Overview

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FSR 1645 is a sparse, very loose object of low C3 quality. Its parallax locates it at a moderate^* distance, above the mid-plane, affected by moderate extinction. It is catalogued as an intermediate-age cluster, but with a large variance across recent sources for the age parameter (see Parameters). It is poorly studied in the literature.

(*): The parallax distance estimate (~3.54 kpc) differs significantly from the median photometric distance (~1.28 kpc).

⚠️ 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 Moderate extinction Intermediate age

Hunt & Reffert (2024)
Classified as open cluster. CMD classes: 0.04 (50th percentile), false positive (human-assigned).

Hunt & Reffert (2023)
Classified as open cluster. CMD classes: 0.04 (50th percentile), false positive (human-assigned).

Morales et al. (2013)
Classified as morphological type 'OC2' (totally exposed cluster without correlation with ATLASGAL emission). Morphological flag: exposed cluster, without submm emission.

Data

🔍 Search references for FSR 1645 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–	200.32	-61.983	0.283	-8.95	-0.906	-5.519
Hunt & Reffert	2024	200.326	-61.989	0.275	-8.983	-0.913	-42.747
Hunt & Reffert	2023	200.326	-61.989	0.275	-8.983	-0.913	-42.747
Just et al.	2023	200.269	-61.922	–	–	–	–
Dias et al.	2018	–	–	–	-6.33	-2.32	–
Dib et al.	2018	200.28	-61.925	–	–	–	–
Sampedro et al.	2017	200.292	-61.946	–	-8.02	-4.3	–
Joshi et al.	2016	200.28	-61.925	–	–	–	–
Kharchenko et al.	2016	200.269	-61.922	–	–	–	–
Dias et al.	2014	200.292	-61.946	–	-8.34	-4.77	–
Kharchenko et al.	2013	200.28	-61.925	–	-9.82	-0.45	–
Morales et al.	2013	200.292	-61.946	–	–	–	–
Froebrich et al.	2007	200.292	-61.946	–	–	–	–
Dias et al.	2002	200.292	-61.946	–	-8.34	-4.77	–

💡 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–	1.28	1.64	1.39	100	–	184	–	–
Hunt & Reffert	2024	3.39	2.53	1.39	2014	–	312⁽¹⁾	–	–
Hunt & Reffert	2023	3.39	2.53	1.39	2014	–	–	–	–
Just et al.	2023	–	–	–	100	–	55	–	–
Dib et al.	2018	1.28	–	–	100	–	–	–	–
Joshi et al.	2016	1.28	1.64	–	100	–	–	–	–
Kharchenko et al.	2016	1.28	1.64	–	100	–	–	–	–
Kharchenko et al.	2013	1.28	1.64	–	100	–	–	–	–
Dias et al.	2002	1.28	1.64	–	100	–	–	–	–

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

Visualization

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