PTB 9

(MWSC 3763)

0.01 UTI

1.0

C_N

1.0

C_dens

1.0

C_C3

0.45

C_lit

0.02

C_dup

N₅₀ (P>50% members) 801

Stellar density (N₅₀/rad) 81.8 [N/pc²]

C3 classification AA

C_N 1.0 Very rich
C_dens 1.0 Very dense
C_C3 1.0 Very high quality
C_lit 0.45 Poorly studied
C_dup 0.02 Very likely duplicate

📥 Members 📊 Colab 🔬 Bayestar19

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

Overview

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PTB 9 is a very rich, very dense object of very high C3 quality. Its parallax locates it at a close distance, above the mid-plane, affected by moderate extinction. It is catalogued as a massive, near-solar metallicity, old cluster, but with a large variance across recent sources for the mass parameter (see Parameters). It is poorly 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. See table with shared members information.

Close Moderate extinction Massive Near-solar metallicity Old

Cavallo et al. (2024)
Gold sample.

Data

🔍 Search references for PTB 9 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–	357.454	68.038	1.032	1.484	3.979	-44.717
Hu & Soubiran	2025	357.449	68.04	–	–	–	–
Hunt & Reffert	2024	357.495	68.031	1.033	1.482	3.963	-44.265
Cavallo et al.	2024	357.449	68.04	1.033	–	–	–
Hunt & Reffert	2023	357.495	68.031	1.033	1.482	3.963	-44.265
Just et al.	2023	357.495	68.03	–	–	–	–
Kharchenko et al.	2016	357.495	68.03	–	–	–	–
Kharchenko et al.	2013	357.502	68.033	–	-2.8	0.04	–
Kharchenko et al.	2012	357.502	68.033	–	-2.8	0.04	–

💡 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–	0.85	2.17	1.04	1175	0.060	1387	–	–
Hu & Soubiran	2025	–	–	–	–	0.150⁽⁵⁾	–	–	–
Hunt & Reffert	2024	–	–	–	–	–	2676⁽¹⁾	–	–
Cavallo et al.	2024	1.04	2.89	–	813	-0.030	–	–	–
Hunt & Reffert	2023	0.93	2.55	1.04	871	–	–	–	–
Just et al.	2023	–	–	–	1175	–	98	–	–
Kharchenko et al.	2016	0.85	2.17	–	1175	–	–	–	–
Kharchenko et al.	2013	0.85	2.17	–	1175	–	–	–	–
Kharchenko et al.	2012	0.85	2.17	–	1175	–	–	–	–

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

Cluster	%	RA	DEC	Plx	pmRA	pmDE	Rv	UTI
Melotte 244	98.1	357.45	68.04	1.03	1.48	3.98	-44.73	1.0

💡 Note: The % column shows the percentage of members that PTB 9 shares with each listed object.

Visualization

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