Blanco 1

(MWSC 7; zeta Scl; OCL 43; ESO 409 09)

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1.0 UTI
1.0
CN
1.0
Cdens
1.0
CC3
1.0
Clit
1.0
Cdup
N50 (P>50% members) 739
Stellar density (N50/rad) 6.4 [N/pc2]
C3 classification AA
  • CN 1.0 Very 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¸
Blanco 1 is a very 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 massive, near-solar metallicity, young cluster, but with a large variance across recent sources for the absorption and age parameters (see Parameters). It is very well-studied in the literature.

Note: This object shares a significant percentage of members with 2 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: 0.18/3.01 Msun

Yan et al. (2026)
Number of WDs: expected from single-star evolution N=3, with probability of formation through binary evolution >=0.5 N=1.

Cavallo et al. (2024)
Gold sample.

Hunt & Reffert (2024)
Classified as open cluster. CMD class: 1.00 (50th percentile).

Richer et al. (2021)
The expected number of WDs is 3.2, 0 WD candidates found, and 0 WD candidates found in the wide search.

Rain et al. (2021)
This cluster was include in (Dias et al., 2002A&A...389..871D, Cat. B/ocl) however, parameters log(t)=7.975, Av=0.031, [Fe/H]=0.00 were taken from Bossini et al. (2019A&A...623A.108B, Cat. J/A+A/623/A108). Ahumada & Lapasset (2007A&A...463..789A, Cat. J/A+A/463/789) cite star Zeta Sculptoris=HD 224990=DR2 2320885329010329216 as a possible blue straggler however, according to Cantat-Gaudin et al. (2018A&A...618A..93C, Cat. J/A+A18/A93) it is not a member.

Ahumada & Lapasset (2007)
Zeta Sculptoris=HD 224990. The identification chart is in the ubvy photometry (1988A&AS...76..101W), where the star Zeta Scl is cited as a blue straggler and is given the following: (b-y)=-0.064, (u-b)= 0.518, m1=0.101, c1=0.441, and spectrum B6III-B5V.

Data
🔍 Search references for Blanco 1 in: SciX Simbad
ℹī¸
Reference Year RA [deg] DEC [deg] Plx [mas] pmRA [mas/yr] pmDE [mas/yr] Rv [km/s]
UCC 99999– 1.222 -29.948 4.226 18.75 2.597 5.193
Yan et al. 2026 0.915 -30.011 4.232 18.725 2.593 –
Malhotra et al. 2026 0.767 -29.815 – – – –
Li et al. 2025 0.853 -29.958 4.21 18.739 2.602 –
Alfonso et al. 2024 1.356 -29.922 4.189 18.721 2.605 –
Hunt & Reffert 2024 0.915 -30.011 4.232 18.725 2.593 4.217
Cavallo et al. 2024 0.861 -29.907 4.228 – – –
Hunt & Reffert 2023 0.915 -30.011 4.232 18.725 2.593 4.217
Almeida et al. 2023 31.717 -30.047 – – – –
Just et al. 2023 0.878 -30.003 – – – –
He et al. 2022 0.872 -29.975 4.224 18.738 2.606 –
Tarricq et al. 2022 0.72 -30.116 4.219 18.722 2.567 –
Jaehnig et al. 2021 1.003 -29.939 4.231 18.737 2.602 –
Rain et al. 2021 0.853 -29.958 4.21 18.739 2.602 –
Richer et al. 2021 0.964 -29.945 4.202 18.7 2.648 –
Dias et al. 2021 1.634 -29.941 4.204 18.689 2.724 5.754
Spina et al. 2021 1.099 -29.953 4.191 18.729 2.63 –
Cantat-Gaudin et al. 2020 0.853 -29.958 4.21 18.739 2.602 –
Cantat-Gaudin & Anders 2020 0.853 -29.958 4.21 18.739 2.602 –
Bossini et al. 2019 0.853 -29.958 – – – –
Soubiran et al. 2018 0.853 -29.958 – – – 5.76
Bica et al. 2019 1.027 -29.832 – – – –
Cantat-Gaudin et al. 2018 0.853 -29.958 4.21 18.739 2.602 –
Yen et al. 2018 1.056 -29.928 4.11 18.65 2.63 –
Loktin & Popova 2017 1.035 -29.833 – 20.17 3.0 5.5
Kharchenko et al. 2016 0.878 -30.003 – – – –
Dias et al. 2014 1.029 -29.833 – 9.84 -3.82 –
Kharchenko et al. 2013 0.885 -30.0 – 19.71 2.28 5.5
Gozha et al. 2012 1.029 -29.833 – – – –
Piskunov et al. 2008 0.822 -30.143 – – – –
Kharchenko et al. 2007 1.03 -29.83 – 2.9 – 3.58
Piskunov et al. 2007 0.822 -30.143 – – – –
Ahumada & Lapasset 2007 1.025 -29.833 – – – –
van den Bergh 2006 0.825 -30.133 – – – –
Kharchenko et al. 2005 0.82 -30.14 – 19.86 2.37 3.58
Kharchenko et al. 2003 0.82 -30.14 – 19.86 3.37 –
Chen et al. 2003 1.063 -29.882 – 20.17 3.0 5.0
Dias et al. 2002 1.029 -29.833 – 20.17 3.0 5.53

💡 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– 0.24 0.03 0.4 93 0.000 1725 0.23 0
Yan et al. 2026 – – – 104 – – – –
Malhotra et al. 2026 0.24 0.02 – 279 0.040 – – –
Li et al. 2025 0.25 0.16 – 85 0.055 – – –
Alfonso et al. 2024 0.24 0.01 – 79 -0.015 – – –
Hunt & Reffert 2024 – – – – – 465(1) – –
Cavallo et al. 2024 0.24 0.36 – 83 0.050 – – –
Hunt & Reffert 2023 0.24 0.06 0.40 173 – – – –
Almeida et al. 2023 0.23 0.01 – 100 -0.024 338(1) 0.23 –
Just et al. 2023 – – – 56 – 436 – –
He et al. 2022 – 0.05 – 63 – – – –
Spina et al. 2022 – – – – -0.053 – – –
Tarricq et al. 2022 0.24 – – 107 – – – –
Jaehnig et al. 2021 0.23(1) – – – – – – –
Rain et al. 2021 0.24 0.03 – 93 – – – 0
Richer et al. 2021 – 0.09 – 105 – – – –
Dias et al. 2021 0.24 0.06 – 103 -0.016 – – –
Spina et al. 2021 0.24 – – 105 -0.056(20) – – –
Cantat-Gaudin et al. 2020 0.24 0.01 – 105 – – – –
Kounkel et al. 2020 0.25 0.24 – 91 – – – –
Cantat-Gaudin & Anders 2020 0.24 – – – – – – –
Bossini et al. 2019 0.24 0.03 – 94 0.000 – – –
Soubiran et al. 2018 0.24 – – – – – – –
Cantat-Gaudin et al. 2018 0.24 – – – – – – –
Yen et al. 2018 0.25 0.02 – 145 – – – –
Loktin & Popova 2017 0.25 0.03 – 63 – – – –
Kharchenko et al. 2016 0.25 0.04 – 56 – – – –
Kharchenko et al. 2013 0.25 0.04 – 56 -0.188 – – –
Gozha et al. 2012 0.27 – – 63 0.040 3020 – –
Piskunov et al. 2008 0.27 0.03 – 209 – 4426(1) – –
Piskunov et al. 2007 0.27 0.03 – 209 – 2985 – –
Ahumada & Lapasset 2007 – 0.03 – 63 – – – 1
van den Bergh 2006 0.27 0.03 – 63 – – – –
Kharchenko et al. 2005 0.27 0.03 – 209 – – – –
Kharchenko et al. 2003 0.26 0.03 – – – – – –
Chen et al. 2003 0.27 0.03 – 60 0.230(1) – – –
Dias et al. 2002 0.27 0.03 – 63 0.040 – – –

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

Cluster % RA DEC Plx pmRA pmDE Rv UTI
CWWDL 14677 50.1 1.03 -30.01 4.23 18.75 2.61 5.52 0.0
Dzeta Scul 2.3 0.43 -30.2 4.21 18.72 2.39 6.9 0.12

💡 Note: The % column shows the percentage of members that Blanco 1 shares with each listed object.

Visualization
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Blanco 1 UCC
Blanco 1 HUNT23
Blanco 1 CANTAT20
Galactocentric position diagram