Alessi 24

(ASCC 89; MWSC 2582; FoF 2389; OCSN 142)

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0.97 UTI
0.84
CN
1.0
Cdens
1.0
CC3
1.0
Clit
1.0
Cdup
N50 (P>50% members) 350
Stellar density (N50/rad) 30.2 [N/pc2]
C3 classification AA
  • CN 0.84 Rich
  • Cdens 1.0 Very dense
  • CC3 1.0 Very high quality
  • Clit 1.0 Very well-studied
  • Cdup 1.0 Unique
đŸ“Ĩ Members 📊 Colab đŸ”Ŧ Bayestar19 MOCAMOCA 🔍 CDS 🔍 Simbad 🔍 CDS (Îą, δ) 🔍 Simbad (Îą, δ)

Overview
ℹī¸
Alessi 24 is a rich, very dense object of very high C3 quality. Its parallax locates it at a very close distance, below the mid-plane, affected by low extinction. It is catalogued as a near-solar metallicity, young cluster, but with a large variance across recent sources for the age and metallicity parameters (see Parameters). It is very well-studied in the literature.

Note: This object shares a very small percentage of members with 3 later reported entries. See table with shared members information.

Malhotra et al. (2026)
Lowest/Highest stellar mass in the catalogue with a mass-ratio estimate: 0.26/3.77 Msun

Yan et al. (2026)
Number of WDs: expected from single-star evolution N=2, with probability of formation through binary evolution >=0.5 N=1.

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

Cavallo et al. (2024)
Gold sample.

Hunt & Reffert (2024)
Classified as open cluster. CMD class: 0.99 (50th percentile).

Hunt & Reffert (2023)
Classified as open cluster. CMD class: 0.99 (50th percentile).

Bica et al. (2019)
Web updates in DAML02, some were later removed (2003 to 2010). List of clusters and alike reported by B. Alessi. The Preliminary Amateur Open Cluster Catalog, Version 08/03/2003.

Data
🔍 Search references for Alessi 24 in: SciX Simbad
ℹī¸
Reference Year RA [deg] DEC [deg] Plx [mas] pmRA [mas/yr] pmDE [mas/yr] Rv [km/s]
UCC 99999– 260.778 -62.718 2.058 -0.451 -8.976 9.223
Yan et al. 2026 260.978 -62.818 2.042 -0.43 -8.963 –
Malhotra et al. 2026 260.803 -62.665 – – – –
Li et al. 2025 260.764 -62.693 2.059 -0.488 -8.999 –
Wei et al. 2025 260.776 -62.653 2.07 -0.483 -8.939 –
Almeida et al. 2025 260.654 -62.784 – – – –
Alfonso et al. 2024 260.809 -62.61 2.019 -0.461 -8.946 –
Hunt & Reffert 2024 260.978 -62.818 2.042 -0.43 -8.963 9.593
Cavallo et al. 2024 260.777 -62.66 2.06 – – –
Hunt & Reffert 2023 260.978 -62.818 2.042 -0.43 -8.963 9.593
Qin et al. 2023 260.85 -62.66 2.07 -0.48 -8.96 9.67
He et al. 2022 260.842 -62.678 2.07 -0.46 -8.95 –
Tarricq et al. 2022 260.962 -62.61 2.045 -0.505 -8.957 –
Dias et al. 2021 260.654 -62.784 2.063 -0.481 -8.932 7.304
Spina et al. 2021 260.772 -62.674 2.056 -0.435 -8.945 –
Cantat-Gaudin et al. 2020 260.764 -62.693 2.059 -0.488 -8.999 –
Cantat-Gaudin & Anders 2020 260.764 -62.693 2.059 -0.488 -8.999 –
Liu & Pang 2019 260.826 -62.701 2.051 -0.389 -8.956 –
Bossini et al. 2019 260.764 -62.693 – – – –
Soubiran et al. 2018 260.764 -62.693 – – – 12.32
Bica et al. 2019 260.992 -62.864 – – – –
Cantat-Gaudin et al. 2018 260.764 -62.693 2.059 -0.488 -8.999 –
Dib et al. 2018 260.835 -62.65 – – – –
Loktin & Popova 2017 261.0 -62.864 – 1.35 -8.31 -6.95
Dias et al. 2014 261.004 -62.863 – -1.62 -5.22 –
Gozha et al. 2012 261.004 -62.863 – – – –
Piskunov et al. 2008 260.804 -62.641 – – – –
Kharchenko et al. 2007 260.82 -62.64 – 1.1 – 12.3
Piskunov et al. 2007 260.804 -62.641 – – – –
Kharchenko et al. 2005 260.82 -62.64 – 1.35 -8.31 4.0
Dias et al. 2002 261.004 -62.863 – 1.35 -8.31 -6.95

💡 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] Bfrac BSS
UCC 99999– 0.495 0.32 0.53 72 0.079 628 0.14 –
Yan et al. 2026 – – – 72 – – – –
Malhotra et al. 2026 0.48 0.21 – 112 0.079 – – –
Li et al. 2025 0.47 0.30 – 85 -0.034 – – –
Wei et al. 2025 0.62 0.44 – 50 0.250 290 0.14 –
Almeida et al. 2025 0.48 0.24 – 286 – 227 – –
Alfonso et al. 2024 0.50 0.34 – 77 0.078 – – –
Hunt & Reffert 2024 – – – – – 313(1) – –
Cavallo et al. 2024 0.51 0.46 – 26 -0.070 – – –
Hunt & Reffert 2023 0.47 0.16 0.53 100 – – – –
Qin et al. 2023 0.59 0.57 – 141 – – – –
He et al. 2022 – 0.30 – 71 – – – –
Spina et al. 2022 – – – – 0.084 – – –
Tarricq et al. 2022 0.50 – – 74 – – – –
Dias et al. 2021 0.48 0.24 – 286 0.079 – – –
Spina et al. 2021 0.49 – – 72 0.079(20) – – –
Cantat-Gaudin et al. 2020 0.50 0.34 – 72 – – – –
Kounkel et al. 2020 0.48 0.37 – 81 – – – –
Cantat-Gaudin & Anders 2020 0.48 – – – – – – –
Liu & Pang 2019 – – – 66 0.250 – – –
Bossini et al. 2019 0.46 0.34 – 88 -0.154 – – –
Soubiran et al. 2018 0.48 – – – – – – –
Cantat-Gaudin et al. 2018 0.48 – – – – – – –
Dib et al. 2018 0.57 – – 10 – – – –
Loktin & Popova 2017 0.42 0.32 – 11 – – – –
Gozha et al. 2012 0.50 – – 11 – 3090 – –
Piskunov et al. 2008 0.50 0.32 – 11 – 1941(1) – –
Piskunov et al. 2007 0.50 0.32 – 11 – 944 – –
Kharchenko et al. 2005 0.50 0.32 – 11 – – – –
Dias et al. 2002 0.50 0.32 – 11 -0.133 – – –

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

Cluster % RA DEC Plx pmRA pmDE Rv UTI
OC 0638 8.9 261.0 -62.86 2.07 -0.34 -8.94 6.93 0.0
LISC-III 3249 7.4 260.88 -62.08 2.06 -0.56 -8.74 9.26 0.05
OC 0639 7.1 261.07 -62.46 2.04 -0.42 -8.97 8.85 0.0

💡 Note: The % column shows the percentage of members that Alessi 24 shares with each listed object.

Visualization
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Alessi 24 UCC
Alessi 24 HUNT23
Alessi 24 CANTAT20
Galactocentric position diagram