ASCC 21

(OCSN 129)

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0.95 UTI
0.77
CN
1.0
Cdens
1.0
CC3
1.0
Clit
1.0
Cdup
N50 (P>50% members) 154
Stellar density (N50/rad) 19.3 [N/pc2]
C3 classification AA
  • CN 0.77 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¸
ASCC 21 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, very young cluster, but with a large variance across recent sources for the absorption parameter (see Parameters). It is very well-studied in the literature.

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

Liu et al. (2025)
Classified as primordial binary cluster 7 along with Briceno_1, and of multiple system 5 along with ASCC_20 and Briceno_1.

Palma et al. (2025)
Classified as genetic pair P184, along with Briceno_1.

Cavallo et al. (2024)
Gold sample.

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

Data
🔍 Search references for ASCC 21 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– 82.229 3.545 2.893 1.456 -0.613 15.495
Liu et al. 2025 82.21 3.61 2.9 1.53 -0.58 10.17
Li et al. 2025 82.179 3.527 2.866 1.404 -0.632 –
Almeida et al. 2025 82.142 3.477 – – – –
Alfonso et al. 2024 81.835 2.466 2.844 1.436 -0.307 –
Zhang et al. 2024 82.212 3.607 – – – –
Hunt & Reffert 2024 82.212 3.607 2.902 1.532 -0.576 10.168
Celli et al. 2024 82.179 3.527 – – – –
Cavallo et al. 2024 82.364 3.309 2.902 – – –
Hunt & Reffert 2023 82.212 3.607 2.902 1.532 -0.576 10.168
Almeida et al. 2023 82.171 3.439 – – – –
Qin et al. 2023 82.15 3.58 2.91 1.48 -0.6 16.95
Dias et al. 2021 82.142 3.477 2.893 1.381 -0.61 15.313
Cantat-Gaudin et al. 2020 82.179 3.527 2.866 1.404 -0.632 –
Donor et al. 2020 82.26 3.56 – 1.28 -0.29 20.0
Zhong et al. 2020 82.179 3.527 – 1.404 -0.632 28.751
Cantat-Gaudin & Anders 2020 82.179 3.527 2.866 1.404 -0.632 –
Dias et al. 2019 82.179 3.527 2.866 1.404 -0.632 16.034
Bossini et al. 2019 82.179 3.527 – – – –
Soubiran et al. 2018 82.179 3.527 – – – 18.7
Cantat-Gaudin et al. 2018 82.179 3.527 2.866 1.404 -0.632 –
Dias et al. 2014 82.246 3.65 – 1.6 -3.82 –
Gozha et al. 2012 82.246 3.65 – – – –
Piskunov et al. 2008 82.236 3.646 – – – –
Kharchenko et al. 2007 82.24 3.65 – 0.8 – 19.77
Piskunov et al. 2007 82.236 3.646 – – – –
Kharchenko et al. 2005 82.24 3.65 – 0.52 -0.62 19.9

💡 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– 0.34 0.13 0.7 12 -0.034 367 0.27 –
Liu et al. 2025 0.32 0.02 – 16 – – – –
Li et al. 2025 0.31 0.17 – 11 -0.142 – – –
Almeida et al. 2025 0.34 0.24 – 13 – 106 – –
Alfonso et al. 2024 0.34 0.10 – 10 -0.008 – – –
Zhang et al. 2024 – – – – -0.059(1) – – –
Hunt & Reffert 2024 – – – – – 63(1) – –
Celli et al. 2024 – – – 9 – 46 – –
Cavallo et al. 2024 0.34 0.59 – 7 0.070 – – –
Hunt & Reffert 2023 0.33 0.14 0.70 7 – – – –
Almeida et al. 2023 0.34 0.28 – 10 -0.118 367(1) 0.27 –
Qin et al. 2023 0.39 0.34 – 9 – – – –
Dias et al. 2021 0.34 0.24 – 13 -0.008 – – –
Cantat-Gaudin et al. 2020 0.34 0.10 – 9 – – – –
Donor et al. 2020 – – – – -0.180 – – –
Zhong et al. 2020 0.31 0.12 – 7032 -0.108 – – –
Cantat-Gaudin & Anders 2020 0.35 – – – – – – –
Dias et al. 2019 0.35 0.16 – 12 0.169 – – –
Bossini et al. 2019 0.31 0.12 – 11 0.000 – – –
Soubiran et al. 2018 0.35 – – – – – – –
Cantat-Gaudin et al. 2018 0.35 – – – – – – –
Gozha et al. 2012 0.50 – – 13 – 851 – –
Piskunov et al. 2008 0.50 0.09 – 13 – 1102(1) – –
Piskunov et al. 2007 0.50 0.09 – 13 – 557 – –
Kharchenko et al. 2005 0.50 0.09 – 13 – – – –

(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 0327 18.8 82.03 3.76 2.91 1.33 -0.6 15.19 0.03
OC 0331 16.9 82.43 3.56 2.91 1.51 -0.62 13.92 0.0
OC 0329 16.2 81.92 3.65 2.91 1.45 -0.6 15.19 0.01

💡 Note: The % column shows the percentage of members that ASCC 21 shares with each listed object.

Visualization
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ASCC 21 UCC
ASCC 21 HUNT23
ASCC 21 CANTAT20
Galactocentric position diagram