NGC 1901

(MWSC 500)

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0.83 UTI
0.76
CN
0.37
Cdens
1.0
CC3
1.0
Clit
1.0
Cdup
Nm (P>50%) 116
Core radius and density 2.5 [pc], 1.9 [pc-2]
C3 classification AA
  • CN 0.76 Rich
  • Cdens 0.37 Loose
  • 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¸
NGC 1901 is a rich, loose 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, intermediate-age 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 significant percentage of members with a later reported entry. See table with shared members information.

Malhotra et al. (2026)
Lowest/Highest stellar mass in the catalogue with a mass-ratio estimate: 0.25/1.81 Msun

Yan et al. (2026)
Number of WDs: expected from single-star evolution N=16, with probability of formation through binary evolution >=0.5 N=1.

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

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=0.2666, e_all=0.5208.

Ahumada & Lapasset (2007)
Star 4=HD 35094 has a spectrum A5V (1975MSS...C01....0H), appears to belong to a subgroup of bright stars at about 18' from the cluster centre, and is a cluster member (1969Obs....89..104M).

Data
🔍 Search references for NGC 1901 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– 79.534 -68.305 2.387 1.697 12.701 0.978
Yan et al. 2026 79.288 -68.441 2.367 1.703 12.701 –
Malhotra et al. 2026 79.691 -68.154 – – – –
Otto et al. 2026 79.288 -68.441 – 1.54 12.67 53.5
Li et al. 2025 79.561 -68.294 2.358 1.537 12.67 –
Hu & Soubiran 2025 79.579 -68.081 – – – –
Almeida et al. 2025 79.708 -68.299 – – – –
Alfonso et al. 2024 79.758 -68.138 2.356 1.681 12.708 –
Hunt & Reffert 2024 79.288 -68.441 2.367 1.703 12.701 0.327
Cavallo et al. 2024 79.579 -68.081 2.376 – – –
Hunt & Reffert 2023 79.288 -68.441 2.367 1.703 12.701 0.327
Almeida et al. 2023 79.595 -68.409 – – – –
Just et al. 2023 79.561 -68.439 – – – –
He et al. 2022 79.65 -68.229 2.391 1.718 12.716 –
Tarricq et al. 2022 79.391 -68.33 2.408 1.703 12.709 –
Jadhav & Subramaniam 2021 79.561 -68.294 – – – –
Jaehnig et al. 2021 79.293 -68.382 2.392 1.697 12.651 –
Rain et al. 2021 79.561 -68.294 2.358 1.537 12.67 –
Dias et al. 2021 79.708 -68.299 2.356 1.571 12.674 1.259
Spina et al. 2021 79.58 -68.355 2.354 1.584 12.702 –
Cantat-Gaudin et al. 2020 79.561 -68.294 2.358 1.537 12.67 –
Cantat-Gaudin & Anders 2020 79.561 -68.294 2.358 1.537 12.67 –
Bossini et al. 2019 79.561 -68.294 – – – –
Soubiran et al. 2018 79.561 -68.294 – – – 0.85
Cantat-Gaudin et al. 2018 79.561 -68.294 2.358 1.537 12.67 –
Angelo et al. 2019 79.558 -68.444 – – – –
Dib et al. 2018 79.56 -68.44 – – – –
Loktin & Popova 2017 79.545 -68.45 – 1.128 1.752 -2.1
Sampedro et al. 2017 79.546 -68.45 – -1.17 -0.29 –
Joshi et al. 2016 79.56 -68.44 – – – –
Kharchenko et al. 2016 79.561 -68.439 – – – –
Netopil et al. 2016 79.546 -68.45 – – – –
Dias et al. 2014 79.546 -68.45 – 0.01 1.01 –
Kharchenko et al. 2013 79.56 -68.44 – 1.68 9.54 -2.1
Gozha et al. 2012 79.546 -68.45 – – – –
Piskunov et al. 2008 79.567 -68.443 – – – –
Kharchenko et al. 2007 79.56 -68.44 – 0.5 – -9.63
Piskunov et al. 2007 79.567 -68.443 – – – –
Ahumada & Lapasset 2007 79.55 -68.433 – – – –
van den Bergh 2006 79.546 -68.45 – – – –
Kharchenko et al. 2005 79.56 -68.44 – 1.16 9.8 -9.63
Kharchenko et al. 2003 79.5 -68.46 – 2.61 8.91 –
Dias et al. 2002 79.546 -68.45 – -0.03 0.9 0.5
Lynga 1987 79.452 -68.452 – – – –
Sulentic et al. 1973 79.449 -68.441 – – – –

💡 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– 0.42 0.15 0.4 813 -0.080 126 0.35 0
Yan et al. 2026 – – – 891 – – – –
Malhotra et al. 2026 0.42 0.17 – 971 -0.145 – – –
Otto et al. 2026 – – – 891 -0.140(15) – – –
Li et al. 2025 0.41 0.19 – 961 -0.163 – – –
Hu & Soubiran 2025 – – – – -0.290(5) – – –
Almeida et al. 2025 0.42 0.11 – 861 – 91 – –
Alfonso et al. 2024 0.43 0.21 – 764 -0.042 – – –
Hunt & Reffert 2024 0.40 0.12 0.40 283 – 194(1) – –
Cavallo et al. 2024 0.43 0.31 – 537 0.260 – – –
Hunt & Reffert 2023 0.40 0.12 0.40 282 – – – –
Almeida et al. 2023 0.42 0.21 – 771 0.030 197(1) 0.35 –
Just et al. 2023 – – – 708 – 55 – –
He et al. 2022 – 0.25 – 891 – – – –
Spina et al. 2022 – – – – -0.143 – – –
Tarricq et al. 2022 0.42 – – 891 – – – –
Jadhav & Subramaniam 2021 0.43 0.21 – 891 – 167 – 0(1)
Jaehnig et al. 2021 0.42(1) – – – – – – –
Rain et al. 2021 0.42 0.09 – 603 – – – 0
Dias et al. 2021 0.42 0.11 – 861 -0.042 – – –
Spina et al. 2021 0.43 – – 891 -0.145(20) – – –
Cantat-Gaudin et al. 2020 0.43 0.21 – 891 – – – –
Kounkel et al. 2020 0.42 0.05 – 813 – – – –
Cantat-Gaudin & Anders 2020 0.42 – – – – – – –
Bossini et al. 2019 0.41 0.15 – 828 -0.080 – – –
Soubiran et al. 2018 0.42 – – – – – – –
Cantat-Gaudin et al. 2018 0.42 – – – – – – –
Angelo et al. 2019 0.42 – – 500 – 22 – –
Dib et al. 2018 0.41 – – 708 – – – –
Loktin & Popova 2017 0.44 0.15 – 450 – – – –
Joshi et al. 2016 0.41 0.07 – 708 – 126 – –
Kharchenko et al. 2016 0.41 0.07 – 708 – – – –
Netopil et al. 2016 7.95 – – 770 -0.080(2) – – –
Heiter et al. 2014 – – – – -0.080 – – –
Kharchenko et al. 2013 0.41 0.07 – 708 -0.331 – – –
Gozha et al. 2012 0.46 – – 603 – 126 – –
Piskunov et al. 2008 0.41 0.06 – 851 – 160(1) – –
Piskunov et al. 2007 0.41 0.06 – 851 – 88 – –
Ahumada & Lapasset 2007 – 0.19 – 832 – – – 1
van den Bergh 2006 0.41 0.19 – 832 – – – –
Kharchenko et al. 2005 0.41 0.06 – 851 – – – –
Kharchenko et al. 2003 0.44 0.19 – – – – – –
Dias et al. 2002 0.46 0.09 – 603 -0.018 – – –
Lynga 1987 0.30 0.16 – 501 – – – –

(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 14525 52.6 79.33 -68.29 2.4 1.75 12.7 1.1 0.0

💡 Note: The % column shows the percentage of members that NGC 1901 shares with each listed object.

Visualization
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NGC 1901 UCC
NGC 1901 HUNT23
NGC 1901 CANTAT20
Galactocentric position diagram