Tombaugh 2

(Haffner 2; MWSC 1076; OCL 605; ESO 558 07; FSR 1250)

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0.95 UTI
1.0
CN
1.0
Cdens
0.75
CC3
1.0
Clit
1.0
Cdup
N50 (P>50% members) 796
Stellar density (N50/rad) 42.3 [N/pc2]
C3 classification AB
  • CN 1.0 Very rich
  • Cdens 1.0 Very dense
  • CC3 0.75 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¸
Tombaugh 2 is a very rich, very dense object of high C3 quality. Its parallax locates it at a large distance, well below the mid-plane, affected by low extinction. It is catalogued as a very massive, near-solar metallicity, old cluster, but with a large variance across recent sources for the 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.

Almeida et al. (2025)
Mass determination: invalid due to poor quality CMD. Isochrone match: worst 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).

Perren et al. (2022)
A well-populated cluster with nearly 900 identified members. The CMD shows a wide main sequence, a prominent giant branch, and a clear RC; some stars above the TO are likely blue stragglers. ASteCA gives 8.7 kpc and 2.1 Gyr, close to Dias 2021 (9 kpc, 2.3 Gyr) and CG20 (9.3 kpc, 1.6 Gyr). OC02 and MWSC give distances below ~7 kpc; WEBDA gives over ~13 kpc. Frinchaboy 2008 proposed an abundance spread among members and adopted 7.9 kpc and 2.0 Gyr. Villanova 2010 places the cluster at 7.2 kpc. Kubiak 1992, studying variable stars, estimated 4 Gyr and 6.3 kpc.

Ahumada & Lapasset (2007)
Only straggler candidates inside a radius of 2' around the centre of coordinates have been considered.

Data
🔍 Search references for Tombaugh 2 in: SciX Simbad
ℹī¸
Reference Year RA [deg] DEC [deg] Plx [mas] pmRA [mas/yr] pmDE [mas/yr] Rv [km/s]
UCC 99999– 105.777 -20.818 0.107 -0.511 1.401 122.805
Otto et al. 2026 105.777 -20.817 – -0.46 1.35 121.5
Guerco et al. 2025 106.0 -20.8 0.07 -0.51 1.47 121.0
Hu & Soubiran 2025 105.778 -20.814 – – – –
Almeida et al. 2025 105.772 -20.819 – – – –
Hunt & Reffert 2024 105.777 -20.817 0.114 -0.511 1.409 119.628
Cavallo et al. 2024 105.778 -20.814 0.112 – – –
Hunt & Reffert 2023 105.777 -20.817 0.114 -0.511 1.409 119.628
Just et al. 2023 105.766 -20.813 – – – –
Perren et al. 2022 105.773 -20.82 – – – –
Jadhav & Subramaniam 2021 105.773 -20.82 – – – –
Jaehnig et al. 2021 105.773 -20.82 0.107 -0.508 1.366 –
Netopil et al. 2022 105.771 -20.817 – – – 122.47
Rain et al. 2021 105.773 -20.82 0.079 -0.464 1.349 –
Dias et al. 2021 105.772 -20.819 0.085 -0.457 1.351 114.337
Cantat-Gaudin et al. 2020 105.773 -20.82 0.079 -0.464 1.349 –
Cantat-Gaudin & Anders 2020 105.773 -20.82 0.079 -0.464 1.349 –
Bica et al. 2019 105.77 -20.815 – – – –
Cantat-Gaudin et al. 2018 105.773 -20.82 0.079 -0.464 1.349 –
Dias et al. 2018 – – – 0.73 0.39 –
Sampedro et al. 2017 105.771 -20.817 -3.04 4.0 – –
Kharchenko et al. 2016 105.766 -20.813 – – – –
Netopil et al. 2016 105.771 -20.817 – – – –
Dias et al. 2014 105.771 -20.817 – -1.72 3.86 –
Kharchenko et al. 2013 105.771 -20.815 – 1.7 2.01 125.0
Gozha et al. 2012 105.771 -20.817 – – – –
Bukowiecki et al. 2011 105.779 -20.816 – – – –
Kharchenko et al. 2007 105.76 -20.82 – 0.03 – –
Ahumada & Lapasset 2007 105.775 -20.817 – – – –
van den Bergh 2006 105.85 -20.85 – – – –
Chen et al. 2003 105.77 -20.815 – – – –
Dias et al. 2002 105.771 -20.817 – -1.72 3.86 120.9
Lynga 1987 105.842 -20.859 – – – –

💡 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– 8.98 0.89 1.82 1621 -0.350 8478 0.45 17
Otto et al. 2026 – – – 1622 -0.350(15) – – –
Guerco et al. 2025 – – – 1620 -0.350 – – –
Hu & Soubiran 2025 – – – – -0.400(5) – – –
Almeida et al. 2025 8.98 0.89 – 2265 – 8478 – –
Hunt & Reffert 2024 – – – – – 4173(1) – –
Cavallo et al. 2024 6.37 0.93 – 2570 -0.370 – – –
Hunt & Reffert 2023 7.68 0.57 1.82 1698 – – – –
Just et al. 2023 – – – 1023 – 2239 – –
Perren et al. 2022 8.71 1.23 – 2138 -0.480 21000 0.45 –
Spina et al. 2022 – – – – -0.288 – – –
Jadhav & Subramaniam 2021 9.33 0.83 – 1622 – 8859 – 17(1)
Jaehnig et al. 2021 9.81(1) – – – – – – –
Netopil et al. 2022 9.12(1) – – 1995 -0.300(1) – – –
Rain et al. 2021 9.27 0.95 – 1023 – – – 27
Dias et al. 2021 8.98 0.89 – 2265 -0.178 – – –
Cantat-Gaudin et al. 2020 9.33 0.83 – 1622 – – – –
Kounkel et al. 2020 5.98 0.83 – 1820 – – – –
Cantat-Gaudin & Anders 2020 9.27 – – – – – – –
Cantat-Gaudin et al. 2018 9.27 – – – – – – –
Kharchenko et al. 2016 6.57 1.12 – 1023 – – – –
Netopil et al. 2016 15.39 – – 1460 – – – –
Kharchenko et al. 2013 6.57 1.12 – 1023 -0.310 – – –
Gozha et al. 2012 6.08 – – 1023 -0.310 – – –
Bukowiecki et al. 2011 10.38(1) 0.47 – 1259 – – – –
Paunzen et al. 2010 – – – – -0.600 – – –
Ahumada & Lapasset 2007 – 0.25 – 1023 – – – 17
van den Bergh 2006 13.26 0.25 – 1023 – – – –
Chen et al. 2003 6.30 1.26 – 4000 -0.450(1) – – –
Dias et al. 2002 6.08 0.95 – 1023 -0.310 – – –

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

Visualization
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Tombaugh 2 UCC
Tombaugh 2 HUNT23
Tombaugh 2 CANTAT20
Galactocentric position diagram