Riddle 4

(MWSC 167)

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0.91 UTI
0.55
CN
1.0
Cdens
1.0
CC3
1.0
Clit
1.0
Cdup
C3 classification AA
Number of members (P>50%) 60
Radius (P>50% members) 1.8 [arcmin]
  • CN 0.55 Moderately populated
  • 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 🔍 CDS 🔍 Simbad 🔍 CDS (Îą, δ) 🔍 Simbad (Îą, δ)

Overview
ℹī¸
Riddle 4 is a moderately populated, very dense object of very high C3 quality. Its parallax locates it at a moderate distance, near the mid-plane, affected by high extinction. It is catalogued as a near-solar metallicity, young cluster, but with a large variance across recent sources for the age, metallicity, and mass parameters (see Parameters). It is very well-studied in the literature.
Relatively close High extinction Near-solar metallicity Young

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

Cavallo et al. (2024)
Gold sample.

Data
🔍 Search references for Riddle 4 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 – 31.862 60.259 0.345 -0.791 -0.491 -44.579
Li et al. 2025 31.862 60.26 0.339 -0.757 -0.451 –
Almeida et al. 2025 31.858 60.263 – – – –
Hunt & Reffert 2024 31.85 60.262 0.354 -0.806 -0.499 -25.266
Celli et al. 2024 31.862 60.26 – – – –
Cavallo et al. 2024 31.83 60.27 0.352 – – –
Hunt & Reffert 2023 31.85 60.262 0.354 -0.806 -0.499 -25.266
Just et al. 2023 31.848 60.269 – – – –
Dias et al. 2021 31.858 60.263 0.349 -0.764 -0.474 –
Cantat-Gaudin et al. 2020 31.862 60.26 0.339 -0.757 -0.451 –
Cantat-Gaudin & Anders 2020 31.862 60.26 0.339 -0.757 -0.451 –
Dias et al. 2019 31.846 60.257 0.337 -0.761 -0.523 -30.388
Soubiran et al. 2018 31.862 60.26 – – – -34.08
Cantat-Gaudin et al. 2018 31.862 60.26 0.339 -0.757 -0.451 –
Loktin & Popova 2017 31.845 60.257 – 0.414 -1.534 –
Kharchenko et al. 2016 31.848 60.269 – – – –
Kharchenko et al. 2013 31.86 60.271 – 1.01 -1.1 –
Kharchenko et al. 2012 31.86 60.271 – 1.01 -1.1 –
Kronberger et al. 2006 31.845 60.257 – – – –
Dias et al. 2002 31.846 60.257 – 9.08 -6.01 –

💡 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] Bfr BSS
Li et al. 2025 2.23 2.99 – 535 -0.126 – – –
Almeida et al. 2025 2.64 3.04 – 11 – 328 – –
Hunt & Reffert 2024 – – – – – 819* – –
Celli et al. 2024 – – – 27 – 392 – –
Cavallo et al. 2024 3.03 3.04 – 35 0.690 – – –
Hunt & Reffert 2023 2.69 3.29 0.76 15 – – – –
Just et al. 2023 – – – 22 – 11 – –
Dias et al. 2021 2.64 3.04 – 11 -0.109 – – –
Cantat-Gaudin et al. 2020 3.08 3.01 – 27 – – – –
Cantat-Gaudin & Anders 2020 2.72 – – – – – – –
Dias et al. 2019 2.27 2.29 – 21 -1.623 – – –
Soubiran et al. 2018 2.72 – – – – – – –
Cantat-Gaudin et al. 2018 2.72 – – – – – – –
Loktin & Popova 2017 1.80 2.13 – 219 – – – –
Kharchenko et al. 2016 2.20 3.25 – 22 – – – –
Kharchenko et al. 2013 2.20 3.25 – 22 – – – –
Kharchenko et al. 2012 2.20 3.25 – 22 – – – –
Dias et al. 2002 2.80 3.41 – 40 – – – –

(*): Indicates that this parameter is assigned more than one value in the corresponding reference.

Visualization
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Riddle 4 UCC
Riddle 4 HUNT23
Riddle 4 CANTAT20
Galactocentric position diagram