Ruprecht 91

(MWSC 1855; OCL 824; ESO 169 01; FoF 2237)

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0.92 UTI
0.83
CN
1.0
Cdens
0.75
CC3
1.0
Clit
1.0
Cdup
C3 classification AB
Number of members (P>50%) 323
Radius (P>50% members) 12.7 [arcmin]
  • CN 0.83 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 🔍 CDS 🔍 Simbad 🔍 CDS (Îą, δ) 🔍 Simbad (Îą, δ)

Overview
ℹī¸
Ruprecht 91 is a rich, very dense object of high C3 quality. Its parallax locates it at a relatively close distance, near the mid-plane, affected by low extinction. It is catalogued as a near-solar metallicity, intermediate-age 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.
Relatively close Low extinction Near-solar metallicity Intermediate age

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

Cavallo et al. (2024)
Gold sample.

Data
🔍 Search references for Ruprecht 91 in: SciX Simbad
ℹī¸
Reference Year RA [deg] DEC [deg] Plx [mas] pmRA [mas/yr] pmDE [mas/yr] Rv [km/s]
UCC – 161.963 -57.49 0.946 -11.222 2.457 0.794
Li et al. 2025 161.964 -57.483 0.927 -11.179 2.421 –
Wei et al. 2025 161.966 -57.496 0.951 -11.238 2.46 –
Almeida et al. 2025 161.926 -57.486 – – – –
Hunt & Reffert 2024 161.967 -57.488 0.943 -11.098 2.406 3.169
Cavallo et al. 2024 161.919 -57.54 0.94 – – –
Hunt & Reffert 2023 161.967 -57.488 0.943 -11.098 2.406 3.169
Almeida et al. 2023 161.948 -57.482 – – – –
Just et al. 2023 161.903 -57.467 – – – –
He et al. 2022 161.913 -57.497 0.95 -11.231 2.467 –
Tarricq et al. 2022 161.984 -57.471 0.95 -11.241 2.456 –
Dias et al. 2021 161.926 -57.486 0.925 -11.187 2.442 0.878
Cantat-Gaudin et al. 2020 161.964 -57.483 0.927 -11.179 2.421 –
Cantat-Gaudin & Anders 2020 161.964 -57.483 0.927 -11.179 2.421 –
Liu & Pang 2019 161.93 -57.502 0.928 -11.153 2.442 –
Soubiran et al. 2018 161.964 -57.483 – – – 0.74
Bica et al. 2019 161.768 -57.396 – – – –
Cantat-Gaudin et al. 2018 161.964 -57.483 0.927 -11.179 2.421 –
Kharchenko et al. 2016 161.903 -57.467 – – – –
Dias et al. 2014 161.908 -57.467 – -3.05 0.74 –
Kharchenko et al. 2013 161.91 -57.47 – -9.86 3.45 5.4
Gozha et al. 2012 161.908 -57.467 – – – –
Piskunov et al. 2008 161.907 -57.469 – – – –
Kharchenko et al. 2007 161.91 -57.47 – 0.15 – 7.3
Kharchenko et al. 2005 161.91 -57.47 – -11.1 3.11 7.3
Kharchenko et al. 2003 161.91 -57.48 – -10.86 3.54 –
Dias et al. 2002 161.908 -57.467 – -3.08 0.64 -10.58

💡 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 0.94 0.36 – 95 -0.249 – – –
Wei et al. 2025 1.09 0.31 – 191 0.250 698 0.35 –
Almeida et al. 2025 1.00 0.31 – 112 – 534 – –
Hunt & Reffert 2024 – – – – – 1036* – –
Cavallo et al. 2024 1.01 0.36 – 178 0.140 – – –
Hunt & Reffert 2023 1.00 0.12 0.66 149 – – – –
Almeida et al. 2023 1.02 0.32 – 113 0.014 477* 0.45 –
Just et al. 2023 – – – 254 – 19 – –
He et al. 2022 – 0.40 – 79 – – – –
Tarricq et al. 2022 1.04 – – 145 – – – –
Dias et al. 2021 1.00 0.31 – 112 0.061 – – –
Cantat-Gaudin et al. 2020 1.07 0.19 – 138 – – – –
Cantat-Gaudin & Anders 2020 1.05 – – – – – – –
Liu & Pang 2019 – – – 55 -0.250 – – –
Soubiran et al. 2018 1.05 – – – – – – –
Cantat-Gaudin et al. 2018 1.05 – – – – – – –
Kharchenko et al. 2016 1.09 0.03 – 254 – – – –
Kharchenko et al. 2013 1.09 0.03 – 254 – – – –
Gozha et al. 2012 0.77 – – 427 – 66 – –
Piskunov et al. 2008 0.90 0.03 – 427 – – – –
Kharchenko et al. 2005 0.90 0.03 – 427 – – – –
Kharchenko et al. 2003 0.77 0.06 – – – – – –
Dias et al. 2002 0.90 0.03 – 427 – – – –

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

Visualization
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Ruprecht 91 UCC
Ruprecht 91 HUNT23
Ruprecht 91 CANTAT20
Galactocentric position diagram