IC 2581

(MWSC 1805)

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0.95 UTI
0.77
CN
1.0
Cdens
1.0
CC3
1.0
Clit
1.0
Cdup
Nm (P>50%) 149
Core radius and density 1.6 [pc], 6.2 [pc-2]
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
πŸ“₯ Members πŸ“Š Colab πŸ”¬ Bayestar19 MOCAMOCA πŸ” CDS πŸ” Simbad πŸ” CDS (Ξ±, Ξ΄) πŸ” Simbad (Ξ±, Ξ΄)

Overview
ℹ️
IC 2581 is a rich, very dense object of very high C3 quality. Its parallax locates it at a moderate distance, near the mid-plane, affected by moderate extinction. It is catalogued as a near-solar metallicity, very young cluster (see Parameters). It is very well-studied in the literature.

Liu et al. (2025)
Classified as primordial binary cluster 266 along with HSC_2342, and of multiple system 64 along with NGC_3324 and HSC_2342.

Palma et al. (2025)
Part of multiple system G151, along with NGC_3324, HSC_2358 and HSC_2342.

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: 0.99 (50th percentile).

Hunt & Reffert (2023)
Classified as open cluster. CMD class: 0.99 (50th percentile).

Hu et al. (2021)
Ellipticities (core, all): e_core=0.059, e_all=0.0999.

Piecka & Paunzen (2021)
Belongs to cluster aggregate 'Agg21' along with Collinder 220.

Ahumada & Lapasset (2007)
The dereddened colour-magnitude diagram in (1978AJ.....83.1081T) was examined.

Data
πŸ” Search references for IC 2581 in: SciX Simbad
ℹ️
Reference Year RA [deg] DEC [deg] Plx [mas] pmRA [mas/yr] pmDE [mas/yr] Rv [km/s]
UCC 99999– 156.863 -57.624 0.371 -7.279 3.596 -31.516
Liu et al. 2025 156.87 -57.63 0.37 -7.29 3.6 –
Li et al. 2025 156.867 -57.626 0.352 -7.275 3.594 –
Almeida et al. 2025 156.863 -57.625 – – – –
Hunt & Reffert 2024 156.874 -57.63 0.372 -7.288 3.601 –
Celli et al. 2024 156.867 -57.626 – – – –
Cavallo et al. 2024 156.852 -57.624 0.372 – – –
Hunt & Reffert 2023 156.874 -57.63 0.372 -7.288 3.601 –
Almeida et al. 2023 156.849 -57.624 – – – –
Just et al. 2023 156.895 -57.636 – – – –
Jaehnig et al. 2021 156.868 -57.627 0.382 -7.278 3.595 –
Rain et al. 2021 156.867 -57.626 0.352 -7.275 3.594 –
Dias et al. 2021 156.863 -57.625 0.349 -7.276 3.598 –
Cantat-Gaudin et al. 2020 156.867 -57.626 0.352 -7.275 3.594 –
SΓ‘nchez et al. 2020 156.871 -57.617 – -7.315 3.736 –
Cantat-Gaudin & Anders 2020 156.867 -57.626 0.352 -7.275 3.594 –
Dias et al. 2019 156.871 -57.617 0.349 -7.254 3.614 -4.617
Soubiran et al. 2018 156.867 -57.626 – – – 117.68
Cantat-Gaudin et al. 2018 156.867 -57.626 0.352 -7.275 3.594 –
Dias et al. 2018 – – – -7.56 3.09 –
Loktin & Popova 2017 156.87 -57.616 – -5.61 1.75 -4.6
Sampedro et al. 2017 156.871 -57.617 – -5.63 1.04 –
Kharchenko et al. 2016 156.895 -57.636 – – – –
Dias et al. 2014 156.871 -57.617 – -5.61 1.75 –
Kharchenko et al. 2013 156.9 -57.64 – -5.83 4.0 -4.6
Gozha et al. 2012 156.871 -57.617 – – – –
Bukowiecki et al. 2011 156.929 -57.61 – – – –
Piskunov et al. 2008 156.859 -57.63 – – – –
Kharchenko et al. 2007 156.87 -57.62 – 0.18 – -4.64
Ahumada & Lapasset 2007 156.875 -57.617 – – – –
van den Bergh 2006 156.875 -57.633 – – – –
Kharchenko et al. 2005 156.87 -57.63 – -6.77 3.7 -4.64
Kharchenko et al. 2003 156.81 -57.63 – -7.86 3.15 –
Chen et al. 2003 156.862 -57.637 – -6.32 3.67 -6.0
Dias et al. 2002 156.871 -57.617 – -5.61 1.75 -0.52
Dambis 1999 156.871 -57.617 – – – –
Lynga 1987 156.866 -57.644 – – – -6.0
van den Bergh & Hagen 1975 156.375 -57.383 – – – –

πŸ’‘ 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– 2.45 1.34 1.29 14 -0.337 549 0.52 0
Liu et al. 2025 4.27 0.47 – 14 – – – –
Li et al. 2025 2.08 1.30 – 15 -0.252 – – –
Almeida et al. 2025 2.45 1.40 – 13 – 546 – –
Hunt & Reffert 2024 2.55 1.38 1.29 21 – 1089(1) – –
Celli et al. 2024 – – – 10 – 541 – –
Cavallo et al. 2024 2.24 1.40 – 39 -0.110 – – –
Hunt & Reffert 2023 2.55 1.38 1.29 21 – – – –
Almeida et al. 2023 2.42 1.44 – 14 0.041 834(1) 0.52 –
Just et al. 2023 – – – 21 – 396 – –
Jaehnig et al. 2021 2.63(1) – – – – – – –
Rain et al. 2021 2.62 1.29 – 14 – – – 0
Dias et al. 2021 2.45 1.40 – 13 0.010 – – –
Cantat-Gaudin et al. 2020 2.54 1.17 – 10 – – – –
Kounkel et al. 2020 2.45 1.53 – 23 – – – –
Cantat-Gaudin & Anders 2020 2.62 – – – – – – –
Dias et al. 2019 2.27 1.10 – 14 -0.337 – – –
Soubiran et al. 2018 2.62 – – – – – – –
Cantat-Gaudin et al. 2018 2.62 – – – – – – –
Loktin & Popova 2017 2.45 1.31 – 14 – – – –
Kharchenko et al. 2016 2.22 1.64 – 21 – – – –
Kharchenko et al. 2013 2.22 1.64 – 21 -0.340 – – –
Bukowiecki et al. 2012 – – – – – 549 – –
Gozha et al. 2012 2.45 – – 14 -0.340 2138 – –
Bukowiecki et al. 2011 2.51(1) 1.48 – 13 – – – –
Piskunov et al. 2008 2.45 1.42 – 17 – – – –
Ahumada & Lapasset 2007 – 1.32 – 14 – – – 0
van den Bergh 2006 2.45 1.32 – 14 – – – –
Kharchenko et al. 2005 2.45 1.42 – 17 – – – –
Kharchenko et al. 2003 2.44 1.32 – – – – – –
Chen et al. 2003 2.45 1.31 – 10 -0.340(1) – – –
Dias et al. 2002 2.45 1.31 – 14 -0.340 – – –
Dambis 1999 2.17 1.34 – 13 – – – –
Lynga 1987 1.66 1.29 – 10 – – – –

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

Visualization
ℹ️
IC 2581 UCC
IC 2581 HUNT23
IC 2581 CANTAT20
Galactocentric position diagram