NGC 6639

(MWSC 2934; OCL 57)

0.35 UTI

0.0

C_N

0.03

C_dens

0.62

C_C3

0.55

C_lit

1.0

C_dup

C3 classification AC

Number of members (P>50%) 15

Radius (P>50% members) 3.9 [arcmin]

C_N 0.0 Sparse
C_dens 0.03 Very loose
C_C3 0.62 Intermediate quality
C_lit 0.55 Moderately studied
C_dup 1.0 Unique

📥 Members 📊 Colab 🔬 Bayestar19 🔍 CDS 🔍 Simbad 🔍 CDS (α, δ) 🔍 Simbad (α, δ)

Overview

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NGC 6639 is a sparse, very loose object of intermediate C3 quality. Its parallax locates it at a large^* distance, below the mid-plane, affected by low extinction. It is catalogued as an intermediate-age cluster (see Parameters). It is moderately studied in the literature.

(*): The parallax distance estimate (~9.19 kpc) differs significantly from the median photometric distance (~0.70 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.

Close Low extinction Intermediate age

Data

🔍 Search references for NGC 6639 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	–	277.725	-13.158	0.109	-3.82	-6.875	120.635
Just et al.	2023	277.732	-13.141	–	–	–	–
Bica et al.	2019	277.716	-13.168	–	–	–	–
Kharchenko et al.	2016	277.732	-13.141	–	–	–	–
Dias et al.	2014	277.746	-13.155	–	-0.36	-2.87	–
Kharchenko et al.	2013	277.74	-13.14	–	1.99	-1.8	7.0
Gozha et al.	2012	277.746	-13.155	–	–	–	–
Piskunov et al.	2008	277.734	-13.155	–	–	–	–
Kharchenko et al.	2007	277.74	-13.15	–	0.18	–	7.0
Kharchenko et al.	2005	277.74	-13.15	–	2.31	-1.5	7.0

💡 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]	Bfr	BSS
Just et al.	2023	–	–	–	851	–	72	–	–
Kharchenko et al.	2016	0.77	0.78	–	851	–	–	–	–
Kharchenko et al.	2013	0.77	0.78	–	851	–	–	–	–
Gozha et al.	2012	0.70	–	–	724	–	62	–	–
Piskunov et al.	2008	0.70	0.62	–	724	–	–	–	–
Kharchenko et al.	2005	0.70	0.62	–	724	–	–	–	–

Visualization

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