NGC 2451B

(MWSC 1322; Platais 7; HIP 37742 Group; FoF 2400)

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0.98 UTI
0.89
CN
1.0
Cdens
1.0
CC3
1.0
Clit
1.0
Cdup
N50 (P>50% members) 485
Stellar density (N50/rad) 39.0 [N/pc2]
C3 classification AA
  • CN 0.89 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¸
NGC 2451B is a rich, very dense object of very high C3 quality. Its parallax locates it at a very 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 and mass parameters (see Parameters). It is very well-studied in the literature.

Note: This object shares a large percentage of members with 2 later reported entries. See table with shared members information.

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

Liu et al. (2025)
Classified as primordial binary cluster 298 along with Collinder_140, and of multiple system 43 along with OCSN_82 and Collinder_140.

Palma et al. (2025)
Part of multiple system G231, along with Theia_249, OCSN_82 and Collinder_140.

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: 0.97 (50th percentile).

Hunt & Reffert (2023)
Classified as open cluster. CMD class: 0.97 (50th percentile).

Richer et al. (2021)
The expected number of WDs is 0.0, 0 WD candidates found, and 10 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)=7.592, Av=0.208, [Fe/H]=0.000 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 DR2 5538726710386348160=HD 63465 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. The same study considered this cluster and NGC 2451A as a single one. In this catalogue, instead, we separate both clusters.

Data
🔍 Search references for NGC 2451B 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– 116.155 -37.95 2.748 -9.622 4.808 14.491
Yan et al. 2026 116.176 -37.942 2.676 -9.4 4.744 –
Liu et al. 2025 116.18 -37.94 2.68 -9.4 4.74 12.84
Li et al. 2025 116.128 -37.954 2.719 -9.671 4.702 –
Almeida et al. 2025 116.008 -37.861 – – – –
Alfonso et al. 2024 115.941 -37.765 2.654 -9.422 4.708 –
Swiggum et al. 2024 116.176 -37.942 2.676 -9.4 4.744 15.008
Hunt & Reffert 2024 116.176 -37.942 2.676 -9.4 4.744 12.842
Cavallo et al. 2024 115.974 -37.592 2.676 – – –
Hunt & Reffert 2023 116.176 -37.942 2.676 -9.4 4.744 12.842
Almeida et al. 2023 116.102 -37.864 – – – –
Just et al. 2023 116.11 -37.668 – – – –
He et al. 2022 116.511 -39.529 2.739 -9.551 4.822 –
Jaehnig et al. 2021 116.134 -37.939 2.759 -9.609 4.824 –
Rain et al. 2021 116.128 -37.954 2.719 -9.671 4.702 –
Richer et al. 2021 116.155 -37.903 2.708 -9.529 4.788 –
Dias et al. 2021 116.008 -37.861 2.719 -9.628 4.715 16.949
Cantat-Gaudin et al. 2020 116.128 -37.954 2.719 -9.671 4.702 –
Cantat-Gaudin & Anders 2020 116.128 -37.954 2.719 -9.671 4.702 –
Liu & Pang 2019 116.167 -37.994 2.723 -9.707 4.799 –
Dias et al. 2019 116.129 -37.954 2.719 -9.671 4.702 22.791
Bossini et al. 2019 116.128 -37.954 – – – –
Soubiran et al. 2018 116.128 -37.954 – – – 16.78
Bica et al. 2019 116.119 -37.663 – – – –
Cantat-Gaudin et al. 2018 116.128 -37.954 2.719 -9.671 4.702 –
Dib et al. 2018 116.115 -37.67 – – – –
Loktin & Popova 2017 116.115 -37.667 – -10.07 5.45 13.7
Sampedro et al. 2017 116.112 -37.667 -0.52 3.42 – –
Joshi et al. 2016 116.115 -37.67 – – – –
Kharchenko et al. 2016 116.11 -37.668 – – – –
Netopil et al. 2016 116.112 -37.667 – – – –
Dias et al. 2014 116.112 -37.667 – -0.56 3.38 –
Kharchenko et al. 2013 116.115 -37.67 – -10.1 6.21 13.7
Gozha et al. 2012 116.113 -37.667 – – – –
Piskunov et al. 2008 116.108 -37.668 – – – –
Kharchenko et al. 2007 116.11 -37.67 – 0.4 – 13.7
Piskunov et al. 2007 116.108 -37.668 – – – –
van den Bergh 2006 116.1 -37.667 – – – –
Kharchenko et al. 2005 116.11 -37.67 – -10.11 4.2 13.7
Kharchenko et al. 2003 116.04 -37.98 – -11.97 2.31 –
Dias et al. 2002 116.112 -37.667 – -10.07 5.45 14.0

💡 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– 0.37 0.21 0.85 44 0.000 120 0.3 0
Yan et al. 2026 – – – 40 – – – –
Liu et al. 2025 0.41 0.10 – 34 – – – –
Li et al. 2025 0.37 0.19 – 42 0.157 – – –
Almeida et al. 2025 0.36 0.31 – 46 – 327 – –
Alfonso et al. 2024 0.36 0.18 – 38 0.050 – – –
Swiggum et al. 2024 0.37 – – 28 – 670 – –
Hunt & Reffert 2024 – – – – – 354(1) – –
Cavallo et al. 2024 0.39 0.65 – 17 0.030 – – –
Hunt & Reffert 2023 0.36 0.18 0.85 28 – – – –
Almeida et al. 2023 0.35 0.46 – 43 -0.011 367(1) 0.30 –
Just et al. 2023 – – – 170 – 32 – –
He et al. 2022 – 0.55 – 32 – – – –
Spina et al. 2022 – – – – -0.021 – – –
Jaehnig et al. 2021 0.36(1) – – – – – – –
Rain et al. 2021 0.36 0.19 – 39 – – – 0
Richer et al. 2021 – 0.46 – 41 – – – –
Dias et al. 2021 0.36 0.31 – 46 0.050 – – –
Cantat-Gaudin et al. 2020 0.36 0.18 – 41 – – – –
Kounkel et al. 2020 0.37 0.48 – 46 – – – –
Cantat-Gaudin & Anders 2020 0.36 – – – – – – –
Liu & Pang 2019 – – – 38 0.000 – – –
Dias et al. 2019 0.37 0.28 – 36 0.073 – – –
Bossini et al. 2019 0.33 0.21 – 39 0.000 – – –
Soubiran et al. 2018 0.36 – – – – – – –
Cantat-Gaudin et al. 2018 0.36 – – – – – – –
Dib et al. 2018 0.49 – – 170 – – – –
Loktin & Popova 2017 0.40 0.19 – 54 – – – –
Joshi et al. 2016 0.49 0.53 – 170 – 120 – –
Kharchenko et al. 2016 0.49 0.53 – 170 – – – –
Netopil et al. 2016 8.11 – – 50 – – – –
Kharchenko et al. 2013 0.49 0.53 – 170 -0.450 – – –
Gozha et al. 2012 0.30 – – 44 -0.450 120 – –
Piskunov et al. 2008 0.43 0.16 – 76 – 79(1) – –
Piskunov et al. 2007 0.43 0.16 – 76 – 26 – –
van den Bergh 2006 0.30 0.19 – 45 – – – –
Kharchenko et al. 2005 0.43 0.16 – 76 – – – –
Kharchenko et al. 2003 0.43 0.32 – – – – – –
Dias et al. 2002 0.30 0.17 – 44 -0.450 – – –

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

Cluster % RA DEC Plx pmRA pmDE Rv UTI
OCSN 231 83.7 116.18 -37.97 2.75 -9.63 4.83 14.5 0.0
CWWDL 14591 46.0 116.21 -38.02 2.75 -9.67 4.84 14.61 0.0

💡 Note: The % column shows the percentage of members that NGC 2451B shares with each listed object.

Visualization
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NGC 2451B UCC
NGC 2451B HUNT23
NGC 2451B CANTAT20
Galactocentric position diagram