IC 4651

(Melotte 169; Collinder 327; VDBH 224; MWSC 2590; OCL 987; vdBergh-Hagen 224; ESO 228 02; FSR 1738; FoF 2053)

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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) 929
Stellar density (N50/rad) 87.4 [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
πŸ“₯ Members πŸ“Š Colab πŸ”¬ Bayestar19 MOCAMOCA πŸ” CDS πŸ” Simbad πŸ” CDS (Ξ±, Ξ΄) πŸ” Simbad (Ξ±, Ξ΄)

Overview
ℹ️
IC 4651 is a very rich, very dense object of very high C3 quality. Its parallax locates it at a close distance, below the mid-plane, affected by low extinction. It is catalogued as a massive, near-solar metallicity, old cluster, but with a large variance across recent sources for the distance, absorption, age, metallicity, and mass parameters (see Parameters). It is very well-studied in the literature.

Note: This object contains blue stragglers according to at least one source.

Note: This object shares a very small percentage of members with a later reported entry. See table with shared members information.

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

Cavallo et al. (2024)
Gold sample.

Hunt & Reffert (2024)
Classified as open cluster. CMD classes: 1.00 (50th percentile), true positive (human-assigned).

Ahumada & Lapasset (2007)
The colour-magnitude diagrams in (1988AJ.....95.1453A) and (1971ApJ...166...87E) were examined. In the CCD photometric study (1988AJ.....95.1453A) stars 9 and 46 are considered as probable binaries; the presence of many binaries in the turn- off area is also suggested. Stars 9, 40, 46, and 75 are cited as blue stragglers in (1971ApJ...166...87E). Star 46 has a spectrum A5IV, and stars 9 and 75 are non-members according to (1972A&AS....7..231L). Membership probabilities based on radial velocities (2002A&A...386..187M): star 11, 23%, star 75, 61%. The DDO photometry of the cluster giants (1982AJ.....87..360S) finds CN overabundance in the stragglers, and draws attention to the possible relation between this fact and the blue straggler phenomenon. Other clusters with blue stragglers and CN-strong giants (1982AJ.....87..360S): Melotte 66, NGC 2204, NGC 2420, NGC 2682, and NGC 7789. According to (1998A&A...335..517B), star 46 is an X-ray source, a probable cluster member, and a probable binary.

Data
πŸ” Search references for IC 4651 in: SciX Simbad
ℹ️
Reference Year RA [deg] DEC [deg] Plx [mas] pmRA [mas/yr] pmDE [mas/yr] Rv [km/s]
UCC 99999– 261.216 -49.916 1.062 -2.429 -5.053 -29.922
Li et al. 2025 261.212 -49.917 1.056 -2.41 -5.064 –
Hu & Soubiran 2025 261.224 -49.918 – – – –
Wei et al. 2025 261.185 -49.919 1.065 -2.43 -5.048 –
Almeida et al. 2025 261.213 -49.916 – – – –
Alfonso et al. 2024 261.226 -49.902 1.02 -2.423 -5.063 –
Hunt & Reffert 2024 261.192 -49.929 1.061 -2.433 -5.057 -29.704
Cavallo et al. 2024 261.224 -49.918 1.061 – – –
Hunt & Reffert 2023 261.192 -49.929 1.061 -2.433 -5.057 -29.704
Angelo et al. 2023 261.225 -49.962 – -2.43 -5.05 –
Just et al. 2023 261.214 -49.935 – – – –
He et al. 2022 261.202 -49.923 1.064 -2.429 -5.053 –
Dias et al. 2022 261.204 -49.932 1.06 -2.45 -5.071 -30.486
Tarricq et al. 2022 261.198 -49.929 1.062 -2.425 -5.049 –
Jadhav & Subramaniam 2021 261.212 -49.917 – – – –
Jaehnig et al. 2021 261.194 -49.924 1.087 -2.419 -5.029 –
Rain et al. 2021 261.212 -49.917 1.056 -2.41 -5.064 –
Dias et al. 2021 261.213 -49.916 1.06 -2.412 -5.05 -30.029
Cantat-Gaudin et al. 2020 261.212 -49.917 1.056 -2.41 -5.064 –
SΓ‘nchez et al. 2020 261.204 -49.933 – -2.438 -5.132 –
Cantat-Gaudin & Anders 2020 261.212 -49.917 1.056 -2.41 -5.064 –
Liu & Pang 2019 261.216 -49.918 1.059 -2.408 -5.053 –
Soubiran et al. 2018 261.212 -49.917 – – – -30.33
Bica et al. 2019 261.214 -49.947 – – – –
Cantat-Gaudin et al. 2018 261.212 -49.917 1.056 -2.41 -5.064 –
Loktin & Popova 2017 261.195 -49.939 – -2.078 -3.679 -31.0
Kharchenko et al. 2016 261.214 -49.935 – – – –
Dias et al. 2014 261.204 -49.933 – -1.57 -2.62 –
Kharchenko et al. 2013 261.225 -49.935 – -0.85 -2.2 -31.0
Gozha et al. 2012 261.204 -49.933 – – – –
Bukowiecki et al. 2011 261.196 -49.938 – – – –
Piskunov et al. 2008 261.197 -49.928 – – – –
Kharchenko et al. 2007 261.21 -49.93 – 0.18 – –
Ahumada & Lapasset 2007 261.175 -49.933 – – – –
van den Bergh 2006 261.204 -49.933 – – – –
Kharchenko et al. 2005 261.21 -49.93 – -0.81 -2.17 –
Kharchenko et al. 2003 261.19 -49.94 – -1.16 -2.42 –
Chen et al. 2003 261.197 -49.928 – 1.5 -5.35 -31.0
Dias et al. 2002 261.204 -49.933 – -1.57 -2.62 -30.8
Lynga 1987 261.154 -49.934 – – – –

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– 0.92 0.38 0.23 1413 0.076 1590 0.41 5
Li et al. 2025 0.90 0.34 – 2087 0.063 – – –
Hu & Soubiran 2025 – – – – -0.180(5) – – –
Wei et al. 2025 2.81 2.42 – 295 -2.000 1736 0.41 –
Almeida et al. 2025 0.92 0.35 – 2065 – 1947 – –
Alfonso et al. 2024 0.98 0.41 – 1477 0.117 – – –
Hunt & Reffert 2024 – – – – – 2329(1) – –
Cavallo et al. 2024 0.95 0.50 – 1479 0.200 – – –
Hunt & Reffert 2023 0.89 0.19 0.23 1663 – – – –
Angelo et al. 2023 0.84 0.41 – 1995 0.050 14(1) – –
Just et al. 2023 – – – 1778 – 90 – –
He et al. 2022 – 0.60 – 1413 – – – –
Dias et al. 2022 0.92(1) 0.36(1) – 1377(1) 0.115(1) – – –
Tarricq et al. 2022 0.96 – – 1660 – – – –
Jadhav & Subramaniam 2021 0.98 0.42 – 1660 – 3629 – 2(1)
Jaehnig et al. 2021 0.92(1) – – – – – – –
Rain et al. 2021 0.92 0.35 – 1122 – – – 5
Dias et al. 2021 0.92 0.35 – 2065 0.120 – – –
Cantat-Gaudin et al. 2020 0.98 0.42 – 1660 – – – –
Kounkel et al. 2020 0.93 0.70 – 1259 – – – –
Cantat-Gaudin & Anders 2020 0.92 – – – – – – –
Liu & Pang 2019 – – – 295 -2.000 – – –
Soubiran et al. 2018 0.92 – – – – – – –
Cantat-Gaudin et al. 2018 0.92 – – – – – – –
Loktin & Popova 2017 0.89 0.37 – 1140 – – – –
Kharchenko et al. 2016 0.89 0.38 – 1778 – – – –
Kharchenko et al. 2013 0.89 0.38 – 1778 -0.128 – – –
Bukowiecki et al. 2012 – – – – – 1443 – –
Gozha et al. 2012 0.89 – – 1140 0.150 123 – –
Bukowiecki et al. 2011 1.01(1) 0.47 – 1413 – – – –
Piskunov et al. 2008 0.89 0.38 – 832 – – – –
Ahumada & Lapasset 2007 – 0.38 – 1148 – – – 6
van den Bergh 2006 0.89 0.38 – 1148 – – – –
Kharchenko et al. 2005 0.89 0.38 – 832 – – – –
Kharchenko et al. 2003 0.89 0.38 – – – – – –
Chen et al. 2003 0.89 0.37 – 1140 0.090(1) – – –
Dias et al. 2002 0.89 0.37 – 1140 0.150 – – –
Lynga 1987 0.71 0.32 – 2399 -0.160 – – –

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

Cluster % RA DEC Plx pmRA pmDE Rv UTI
CWNU 1213 2.3 261.23 -49.89 1.03 -2.31 -5.04 -30.84 0.06

πŸ’‘ Note: The % column shows the percentage of members that IC 4651 shares with each listed object.

Visualization
ℹ️
IC 4651 UCC
IC 4651 HUNT23
IC 4651 CANTAT20
Galactocentric position diagram