PTB 4

(MWSC 3718)

0.13 UTI

0.0

C_N

0.04

C_dens

0.12

C_C3

0.25

C_lit

1.0

C_dup

C3 classification DC

Number of members (P>50%) 17

Radius (P>50% members) 6.1 [arcmin]

C_N 0.0 Sparse
C_dens 0.04 Very loose
C_C3 0.12 Very low quality
C_lit 0.25 Poorly studied
C_dup 1.0 Unique

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

Overview

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PTB 4 is a sparse, very loose object of very low C3 quality. Its parallax locates it at a large^* distance, well above the mid-plane, affected by high extinction. It is catalogued as a very young cluster (see Parameters). It is poorly studied in the literature.

(*): The parallax distance estimate (~5.46 kpc) differs significantly from the median photometric distance (~2.00 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 High extinction Very young

Data

🔍 Search references for PTB 4 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	–	349.943	70.061	0.183	-2.039	-0.473	-49.14
Just et al.	2023	349.808	70.087	–	–	–	–
Kharchenko et al.	2016	349.808	70.087	–	–	–	–
Kharchenko et al.	2013	349.815	70.09	–	-0.85	-1.59	–
Kharchenko et al.	2012	349.815	70.09	–	-0.85	-1.59	–

💡 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	–	–	–	10	–	211	–	–
Kharchenko et al.	2016	2.00	3.72	–	10	–	–	–	–
Kharchenko et al.	2013	2.00	3.72	–	10	–	–	–	–
Kharchenko et al.	2012	2.00	3.72	–	10	–	–	–	–

Visualization

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