Basel 11a

(MWSC 1162; OCL 584.1; FoF 2084)

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0.89 UTI
0.76
CN
1.0
Cdens
0.75
CC3
0.97
Clit
1.0
Cdup
Nm (P>50%) 133
Core radius and density 1.1 [pc], 11 [pc-2]
C3 classification AB
  • CN 0.76 Rich
  • Cdens 1.0 Very dense
  • CC3 0.75 High quality
  • Clit 0.97 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¸
Basel 11a is a rich, very dense object of high C3 quality. Its parallax locates it at a relatively close distance, near 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 parameter (see Parameters). It is very well-studied in the literature.

Palma et al. (2025)
Classified as optical pair P82, along with HSC_1797.

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

Cavallo et al. (2024)
Gold sample.

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

Hunt & Reffert (2023)
Classified as open cluster. CMD class: 1.00 (50th percentile).

Hu et al. (2021)
Ellipticities (core, all): e_core=0.3156, e_all=0.048.

Data
🔍 Search references for Basel 11a in: SciX Simbad
ℹī¸
Reference Year RA [deg] DEC [deg] Plx [mas] pmRA [mas/yr] pmDE [mas/yr] Rv [km/s]
UCC 99999– 109.301 -13.99 0.718 -1.596 0.964 25.779
Li et al. 2025 109.296 -13.988 0.709 -1.581 0.929 –
Almeida et al. 2025 109.303 -13.981 – – – –
Hunt & Reffert 2024 109.293 -13.983 0.715 -1.605 0.976 31.379
Cavallo et al. 2024 109.314 -13.987 0.716 – – –
Hunt & Reffert 2023 109.293 -13.983 0.715 -1.605 0.976 31.379
Almeida et al. 2023 109.315 -13.986 – – – –
Just et al. 2023 109.272 -13.98 – – – –
Dias et al. 2021 109.303 -13.981 0.71 -1.584 0.935 –
Cantat-Gaudin et al. 2020 109.296 -13.988 0.709 -1.581 0.929 –
Cantat-Gaudin & Anders 2020 109.296 -13.988 0.709 -1.581 0.929 –
Liu & Pang 2019 109.299 -13.973 0.703 -1.613 0.919 –
Soubiran et al. 2018 109.296 -13.988 – – – 80.49
Bica et al. 2019 109.315 -13.962 – – – –
Cantat-Gaudin et al. 2018 109.296 -13.988 0.709 -1.581 0.929 –
Dias et al. 2018 – – – -1.72 1.85 –
Dib et al. 2018 109.278 -13.982 – – – –
Loktin & Popova 2017 109.275 -13.966 – -0.565 -3.607 –
Sampedro et al. 2017 109.275 -13.967 – -0.43 -0.61 –
Joshi et al. 2016 109.278 -13.982 – – – –
Kharchenko et al. 2016 109.272 -13.98 – – – –
Dias et al. 2014 109.275 -13.967 – -0.94 0.33 –
Kharchenko et al. 2013 109.278 -13.982 – -1.09 -0.68 –
Bukowiecki et al. 2011 109.304 -13.962 – – – –
Piskunov et al. 2008 109.269 -13.963 – – – –
van den Bergh 2006 109.275 -13.967 – – – –
Kharchenko et al. 2005 109.27 -13.97 – -2.49 1.0 –
Kharchenko et al. 2003 109.27 -13.97 – -2.55 1.58 –
Dias et al. 2002 109.275 -13.967 – -0.94 0.33 –
Lynga 1987 109.274 -13.972 – – – –

💡 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– 1.36 0.57 0.84 80 -0.041 225 0.52 –
Li et al. 2025 1.27 0.55 – 80 -0.164 – – –
Almeida et al. 2025 1.36 0.65 – 80 – 305 – –
Hunt & Reffert 2024 1.31 0.27 0.84 135 – 425(1) – –
Cavallo et al. 2024 1.34 0.49 – 95 0.130 – – –
Hunt & Reffert 2023 1.31 0.27 0.84 135 – – – –
Almeida et al. 2023 1.32 0.58 – 109 -0.126 242(1) 0.52 –
Just et al. 2023 – – – 26 – 148 – –
Tarricq et al. 2022 1.32 – – 100 – – – –
Dias et al. 2021 1.36 0.65 – 80 -0.041 – – –
Cantat-Gaudin et al. 2020 1.36 0.33 – 95 – – – –
Kounkel et al. 2020 1.35 0.53 – 87 – – – –
Cantat-Gaudin & Anders 2020 1.35 – – – – – – –
Liu & Pang 2019 – – – 40 0.250 – – –
Soubiran et al. 2018 1.35 – – – – – – –
Cantat-Gaudin et al. 2018 1.35 – – – – – – –
Dib et al. 2018 1.54 – – 26 – – – –
Loktin & Popova 2017 1.71 1.00 – 65 – – – –
Joshi et al. 2016 1.54 0.66 – 26 – 200 – –
Kharchenko et al. 2016 1.54 0.66 – 26 – – – –
Kharchenko et al. 2013 1.54 0.66 – 26 – – – –
Bukowiecki et al. 2012 – – – – – 208 – –
Bukowiecki et al. 2011 1.40(1) 0.35 – 158 – – – –
Piskunov et al. 2008 1.50 0.57 – 26 – – – –
van den Bergh 2006 1.52 0.00 – 200 – – – –
Kharchenko et al. 2005 1.50 0.57 – 26 – – – –
Kharchenko et al. 2003 1.92 0.91 – – – – – –
Dias et al. 2002 1.52 0.00 – 200 – – – –
Lynga 1987 – – – 316 – – – –

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

Visualization
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Basel 11a UCC
Basel 11a HUNT23
Basel 11a CANTAT20
Galactocentric position diagram