Alessi 31

(ASCC 92; MWSC 2723; FoF 2356)

0.96 UTI

0.78

C_N

1.0

C_dens

1.0

C_C3

1.0

C_lit

1.0

C_dup

N₅₀ (P>50% members) 175

Stellar density (N₅₀/rad) 18.5 [N/pc²]

C3 classification AA

C_N 0.78 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 31 is a 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 near-solar metallicity, intermediate-age cluster, but with a large variance across recent sources for the distance, age, metallicity, and mass parameters (see Parameters). It is very well-studied in the literature.

Close Moderate extinction Near-solar metallicity Intermediate age

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

Cavallo et al. (2024)
Gold sample.

Data

🔍 Search references for Alessi 31 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–	267.715	-11.837	1.476	-1.147	-4.172	2.939
Li et al.	2025	267.698	-11.853	1.477	-1.164	-4.122	–
Wei et al.	2025	267.725	-11.842	1.475	-1.136	-4.179	–
Almeida et al.	2025	267.665	-11.882	–	–	–	–
Alfonso et al.	2024	267.719	-11.85	1.442	-1.139	-4.178	–
Hunt & Reffert	2024	267.748	-11.857	1.473	-1.13	-4.167	3.514
Cavallo et al.	2024	267.715	-11.845	1.474	–	–	–
Hunt & Reffert	2023	267.748	-11.857	1.473	-1.13	-4.167	3.514
Just et al.	2023	267.772	-11.881	–	–	–	–
He et al.	2022	267.741	-11.859	1.481	-1.136	-4.208	–
Tarricq et al.	2022	267.747	-11.87	1.503	-1.137	-4.177	–
Dias et al.	2021	267.665	-11.882	1.483	-1.189	-4.091	–
Cantat-Gaudin et al.	2020	267.698	-11.853	1.477	-1.164	-4.122	–
Cantat-Gaudin & Anders	2020	267.698	-11.853	1.477	-1.164	-4.122	–
Liu & Pang	2019	267.752	-11.835	1.474	-1.157	-4.115	–
Soubiran et al.	2018	267.698	-11.853	–	–	–	5.36
Bica et al.	2019	267.68	-12.002	–	–	–	–
Cantat-Gaudin et al.	2018	267.698	-11.853	1.477	-1.164	-4.122	–
Kharchenko et al.	2016	267.772	-11.881	–	–	–	–
Dias et al.	2014	267.675	-12.002	–	-5.29	-2.16	–
Kharchenko et al.	2013	267.78	-11.88	–	-6.63	-5.53	–
Piskunov et al.	2008	267.774	-11.883	–	–	–	–
Kharchenko et al.	2005	267.78	-11.88	–	-7.68	-4.91	–
Dias et al.	2002	267.675	-12.002	–	-5.29	-2.16	–

💡 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–	0.65	1.75	2.5	251	0.285	464	0.47	–
Li et al.	2025	0.55	1.75	–	601	0.147	–	–	–
Wei et al.	2025	2.10	3.31	–	28	-0.750	371	0.47	–
Almeida et al.	2025	0.65	2.15	–	113	–	557	–	–
Alfonso et al.	2024	0.71	1.75	–	79	0.359	–	–	–
Hunt & Reffert	2024	–	–	–	–	–	668⁽¹⁾	–	–
Cavallo et al.	2024	0.70	2.37	–	126	0.320	–	–	–
Hunt & Reffert	2023	0.64	2.23	2.50	150	–	–	–	–
Just et al.	2023	–	–	–	1202	–	25	–	–
He et al.	2022	–	2.70	–	40	–	–	–	–
Tarricq et al.	2022	0.70	–	–	251	–	–	–	–
Dias et al.	2021	0.65	2.15	–	113	0.359	–	–	–
Cantat-Gaudin et al.	2020	0.71	1.75	–	240	–	–	–	–
Cantat-Gaudin & Anders	2020	0.66	–	–	–	–	–	–	–
Liu & Pang	2019	–	–	–	347	0.250	–	–	–
Soubiran et al.	2018	0.66	–	–	–	–	–	–	–
Cantat-Gaudin et al.	2018	0.66	–	–	–	–	–	–	–
Kharchenko et al.	2016	0.64	0.97	–	1202	–	–	–	–
Kharchenko et al.	2013	0.64	0.97	–	1202	–	–	–	–
Piskunov et al.	2008	0.65	0.78	–	1023	–	–	–	–
Kharchenko et al.	2005	0.65	0.78	–	1023	–	–	–	–
Dias et al.	2002	0.65	0.78	–	1023	–	–	–	–

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

Visualization

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