Alessi 4

(MWSC 1786)

0.15 UTI

0.0

C_N

0.24

C_dens

0.0

C_C3

0.25

C_lit

1.0

C_dup

C3 classification DD

Number of members (P>50%) 22

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

C_N 0.0 Sparse
C_dens 0.24 Very loose
C_C3 0.0 Very low quality
C_lit 0.25 Poorly studied
C_dup 1.0 Unique

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

Overview

Alessi 4 is a sparse, very loose object of very low C3 quality. Its parallax locates it at a moderate distance, well above the mid-plane, affected by moderate extinction. It is catalogued as an intermediate-age cluster (see Parameters). It is poorly studied in the literature.

⚠️ 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 Moderate extinction Intermediate age

Dias et al. (2002): Asterism (Alessi, B. S. et al. 2003, A&A 410, 565)

Data

Reference	Year	RA [deg]	DEC [deg]	Plx [mas]	pmRA [mas/yr]	pmDE [mas/yr]	Rv [km/s]
UCC	–	154.075	-34.324	0.415	-7.23	4.261	-0.493
Just et al.	2023	154.051	-34.356	–	–	–	–
Bica et al.	2019	154.051	-34.348	–	–	–	–
Kharchenko et al.	2016	154.051	-34.356	–	–	–	–
Kharchenko et al.	2013	154.057	-34.36	–	-10.65	4.48	–

💡 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	–	–	–	355	–	307	–	–
Kharchenko et al.	2016	2.34	1.48	–	355	–	–	–	–
Kharchenko et al.	2013	2.34	1.48	–	355	–	–	–	–

💡 Note: The parameters are sometimes transformed from their original values to match the format of the columns shown here, see FAQ. The columns DAv, Bfr, BSS correspond to differential extinction, binary fraction, and blue stragglers, respectively. BSS values can be listed as fractions or integers.

Visualization

💡 Note: How are the galactocentric plots generated? See FAQ.