Alessi 9

(MWSC 2670; OCSN 139)

0.95 UTI

0.76

C_N

1.0

C_dens

1.0

C_C3

1.0

C_lit

1.0

C_dup

N₅₀ (P>50% members) 140

Stellar density (N₅₀/rad) 14.9 [N/pc²]

C3 classification AA

C_N 0.76 Rich
C_dens 1.0 Very dense
C_C3 1.0 Very high quality
C_lit 1.0 Very well-studied
C_dup 1.0 Unique

📥 Members 📊 Colab 🔬 Bayestar19

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

Overview

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Alessi 9 is a rich, very dense object of very high C3 quality. Its parallax locates it at a very close distance, near the mid-plane, affected by low extinction. It is catalogued as a near-solar metallicity, intermediate-age cluster, but with a large variance across recent sources for the absorption and metallicity parameters (see Parameters). It is very well-studied in the literature.

Very close Low extinction Near-solar metallicity Intermediate age

Almeida et al. (2025)
Mass determination: good fit. Isochrone match: good fit. Silver sample.

Cavallo et al. (2024)
Gold sample.

Data

🔍 Search references for Alessi 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–	265.926	-46.921	4.783	9.923	-9.068	-6.731
Li et al.	2025	265.974	-47.028	4.822	9.916	-9.157	–
Almeida et al.	2025	266.019	-47.237	–	–	–	–
Alfonso et al.	2024	265.628	-47.181	4.698	9.753	-9.066	–
Hunt & Reffert	2024	265.642	-46.744	4.778	9.831	-9.151	-8.729
Cavallo et al.	2024	265.811	-47.145	4.78	–	–	–
Hunt & Reffert	2023	265.642	-46.744	4.778	9.831	-9.151	-8.729
Qin et al.	2023	265.9	-46.83	4.76	9.77	-9.12	-5.94
Just et al.	2023	266.285	-47.186	–	–	–	–
Tarricq et al.	2022	265.998	-46.885	4.779	9.839	-9.063	–
Dias et al.	2021	266.019	-47.237	4.793	9.929	-9.144	-6.213
Cantat-Gaudin et al.	2020	265.974	-47.028	4.822	9.916	-9.157	–
Cantat-Gaudin & Anders	2020	265.974	-47.028	4.822	9.916	-9.157	–
Soubiran et al.	2018	265.974	-47.028	–	–	–	-6.44
Bica et al.	2019	265.983	-47.18	–	–	–	–
Cantat-Gaudin et al.	2018	265.974	-47.028	4.822	9.916	-9.157	–
Yen et al.	2018	266.249	-47.043	4.94	9.71	-8.81	–
Kharchenko et al.	2016	266.285	-47.186	–	–	–	–
Dias et al.	2014	265.875	-46.967	–	1.11	-2.36	–
Kharchenko et al.	2013	266.295	-47.185	–	10.75	-9.5	-11.6
Gozha et al.	2012	265.875	-46.967	–	–	–	–
Piskunov et al.	2008	265.963	-47.183	–	–	–	–
Kharchenko et al.	2007	265.6	-47.01	–	1.4	–	-11.6
Piskunov et al.	2007	265.963	-47.183	–	–	–	–
van den Bergh	2006	266.0	-47.0	–	–	–	–
Kharchenko et al.	2005	265.98	-47.18	–	11.59	-9.72	-11.6
Alessi et al.	2003	266.0	-47.0	–	10.9	-9.7	–
Dias et al.	2002	265.875	-46.967	–	11.59	-9.72	-11.6

💡 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–	0.21	0.22	0.41	282	-0.002	172	–	–
Li et al.	2025	0.23	0.29	–	151	0.048	–	–	–
Almeida et al.	2025	0.21	0.15	–	392	–	153	–	–
Alfonso et al.	2024	0.21	0.00	–	302	-0.001	–	–	–
Hunt & Reffert	2024	–	–	–	–	–	151⁽¹⁾	–	–
Cavallo et al.	2024	0.21	0.49	–	257	0.310	–	–	–
Hunt & Reffert	2023	0.21	0.12	0.41	411	–	–	–	–
Qin et al.	2023	0.22	0.22	–	282	–	–	–	–
Just et al.	2023	–	–	–	355	–	19	–	–
Tarricq et al.	2022	0.21	–	–	282	–	–	–	–
Dias et al.	2021	0.21	0.15	–	392	-0.002	–	–	–
Cantat-Gaudin et al.	2020	0.21	0.00	–	282	–	–	–	–
Cantat-Gaudin & Anders	2020	0.21	–	–	–	–	–	–	–
Soubiran et al.	2018	0.21	–	–	–	–	–	–	–
Cantat-Gaudin et al.	2018	0.21	–	–	–	–	–	–	–
Yen et al.	2018	0.22	0.28	–	263	–	–	–	–
Kharchenko et al.	2016	0.22	0.32	–	355	–	–	–	–
Kharchenko et al.	2013	0.22	0.32	–	355	-0.580	–	–	–
Gozha et al.	2012	0.21	–	–	–	–	191	–	–
Piskunov et al.	2008	0.20	0.22	–	263	–	480⁽¹⁾	–	–
Piskunov et al.	2007	0.20	0.22	–	263	–	336	–	–
van den Bergh	2006	0.20	0.22	–	251	–	–	–	–
Kharchenko et al.	2005	0.20	0.22	–	263	–	–	–	–
Alessi et al.	2003	0.19	0.22	–	251	–	–	–	–
Dias et al.	2002	0.21	–	–	–	-0.580	–	–	–

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

Visualization

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