Alessi 2

(MWSC 419; LeDrew 4)

0.96 UTI

0.82

C_N

1.0

C_dens

1.0

C_C3

1.0

C_lit

1.0

C_dup

C3 classification AA

Number of members (P>50%) 287

Radius (P>50% members) 27.3 [arcmin]

C_N 0.82 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 🔍 CDS 🔍 Simbad 🔍 CDS (α, δ) 🔍 Simbad (α, δ)

Overview

ℹ️

Alessi 2 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 low extinction. It is catalogued as a near-solar metallicity, intermediate-age cluster, but with a large variance across recent sources for the metallicity and mass parameters (see Parameters). It is very well-studied in the literature.

Close Low extinction Near-solar metallicity Intermediate age

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

Cavallo et al. (2024)
Gold sample.

Data

🔍 Search references for Alessi 2 in: SciX Simbad

ℹ️

Reference	Year	RA [deg]	DEC [deg]	Plx [mas]	pmRA [mas/yr]	pmDE [mas/yr]	Rv [km/s]
UCC	–	71.607	55.181	1.615	-0.915	-1.095	-10.442
Li et al.	2025	71.602	55.199	1.589	-0.904	-1.046	–
Almeida et al.	2025	71.627	55.234	–	–	–	–
Alfonso et al.	2024	71.619	55.181	1.583	-0.925	-1.099	–
Zhang et al.	2024	71.557	55.184	–	–	–	–
Hunt & Reffert	2024	71.557	55.184	1.618	-0.928	-1.095	-10.275
Cavallo et al.	2024	71.648	55.186	1.623	–	–	–
Hunt & Reffert	2023	71.557	55.184	1.618	-0.928	-1.095	-10.275
Almeida et al.	2023	71.511	55.213	–	–	–	–
Just et al.	2023	71.552	55.255	–	–	–	–
He et al.	2022	71.606	55.2	1.624	-0.944	-1.091	–
Dias et al.	2021	71.627	55.234	1.582	-0.896	-1.055	-10.466
Cantat-Gaudin et al.	2020	71.602	55.199	1.589	-0.904	-1.046	–
Cantat-Gaudin & Anders	2020	71.602	55.199	1.589	-0.904	-1.046	–
Bossini et al.	2019	71.602	55.199	–	–	–	–
Soubiran et al.	2018	71.602	55.199	–	–	–	-11.0
Bica et al.	2019	71.561	55.234	–	–	–	–
Cantat-Gaudin et al.	2018	71.602	55.199	1.589	-0.904	-1.046	–
Loktin & Popova	2017	71.505	55.207	–	1.62	-3.654	–
Kharchenko et al.	2016	71.552	55.255	–	–	–	–
Dias et al.	2014	71.508	55.207	–	1.75	0.14	–
Kharchenko et al.	2013	71.565	55.255	–	-0.91	-0.75	–
Kharchenko et al.	2012	71.565	55.255	–	-0.91	-0.75	–
Piskunov et al.	2008	71.548	55.228	–	–	–	–
Piskunov et al.	2007	71.548	55.228	–	–	–	–
van den Bergh	2006	71.6	55.25	–	–	–	–
Kharchenko et al.	2005	71.56	55.23	–	-0.08	0.31	–
Alessi et al.	2003	71.6	55.25	–	0.2	-1.1	–
Dias et al.	2002	71.508	55.207	–	0.25	-1.09	–

💡 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
Li et al.	2025	0.58	0.68	–	538	-0.029	–	–	–
Almeida et al.	2025	0.61	0.81	–	396	–	391	–	–
Alfonso et al.	2024	0.66	0.52	–	701	0.058	–	–	–
Zhang et al.	2024	–	–	–	–	-0.046*	–	–	–
Hunt & Reffert	2024	–	–	–	–	–	289*	–	–
Cavallo et al.	2024	0.62	0.89	–	251	0.270	–	–	–
Hunt & Reffert	2023	0.59	0.57	0.75	264	–	–	–	–
Almeida et al.	2023	0.60	0.92	–	318	-0.086	317*	0.54	–
Just et al.	2023	–	–	–	499	–	28	–	–
He et al.	2022	–	0.85	–	282	–	–	–	–
Tarricq et al.	2022	0.65	–	–	380	–	–	–	–
Dias et al.	2021	0.61	0.81	–	396	0.057	–	–	–
Cantat-Gaudin et al.	2020	0.66	0.52	–	355	–	–	–	–
Cantat-Gaudin & Anders	2020	0.62	–	–	–	–	–	–	–
Bossini et al.	2019	0.59	0.48	–	574	0.000	–	–	–
Soubiran et al.	2018	0.62	–	–	–	–	–	–	–
Cantat-Gaudin et al.	2018	0.62	–	–	–	–	–	–	–
Loktin & Popova	2017	0.57	0.96	–	34	–	–	–	–
Kharchenko et al.	2016	0.52	0.46	–	499	–	–	–	–
Kharchenko et al.	2013	0.52	0.46	–	499	–	–	–	–
Kharchenko et al.	2012	0.52	0.46	–	499	–	–	–	–
Piskunov et al.	2008	0.50	0.56	–	398	–	57*	–	–
Piskunov et al.	2007	0.50	0.56	–	398	–	10	–	–
van den Bergh	2006	0.50	0.56	–	316	–	–	–	–
Kharchenko et al.	2005	0.50	0.56	–	398	–	–	–	–
Alessi et al.	2003	0.50	0.56	–	316	–	–	–	–
Dias et al.	2002	0.50	0.56	–	316	–	–	–	–

(*): Indicates that this parameter is assigned more than one value in the corresponding reference.

Visualization

ℹ️

1 2 3