RSG5

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0.72 UTI
0.81
CN
0.55
Cdens
1.0
CC3
0.61
Clit
1.0
Cdup
Nm (P>50%) 272
Core radius and density 2.7 [pc], 2.8 [pc-2]
C3 classification AA
  • CN 0.81 Rich
  • Cdens 0.55 Moderately dense
  • CC3 1.0 Very high quality
  • Clit 0.61 Moderately studied
  • Cdup 1.0 Unique
đŸ“Ĩ Members 📊 Colab đŸ”Ŧ Bayestar19 MOCAMOCA 🔍 CDS 🔍 Simbad 🔍 CDS (Îą, δ) 🔍 Simbad (Îą, δ)

Overview
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RSG5 is a rich, moderately dense object of very high C3 quality. Its parallax locates it at a very close distance, above the mid-plane, affected by low extinction. It is catalogued as a near-solar metallicity, young cluster, but with a large variance across recent sources for the absorption parameter (see Parameters). It is moderately studied in the literature.

Note: This object shares a large percentage of members with 3 later reported entries. See table with shared members information.

Malhotra et al. (2026)
Lowest/Highest stellar mass in the catalogue with a mass-ratio estimate: 0.18/4.4 Msun

Yan et al. (2026)
Number of WDs: expected from single-star evolution N=1, with probability of formation through binary evolution >=0.5 N=1.

Liu et al. (2025)
Classified as primordial binary cluster 334 along with Theia_96, and as tidal capture (resonant trapping binary) 335 along with Roslund_6, and of multiple system 79 along with Roslund_6 and Theia_96.

Palma et al. (2025)
Part of multiple system G235, along with HSC_680 and Theia_96.

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 class: 1.00 (50th percentile).

Hunt & Reffert (2023)
Classified as open cluster. CMD class: 1.00 (50th percentile).

Hu et al. (2021)
Ellipticities (core, all): e_core=0.524, e_all=0.2148.

Data
🔍 Search references for RSG5 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 99999– 303.5 45.595 2.958 3.623 1.553 -7.389
Yan et al. 2026 303.909 45.738 2.967 3.645 1.597 –
Malhotra et al. 2026 303.558 45.574 – – – –
Liu et al. 2025 303.91 45.74 2.97 3.65 1.6 -3.41
Li et al. 2025 303.482 45.574 2.945 3.573 1.605 –
Almeida et al. 2025 303.557 45.535 – – – –
Alfonso et al. 2024 304.0 46.003 2.907 3.546 1.672 –
Zhang et al. 2024 303.909 45.738 – – – –
Swiggum et al. 2024 303.909 45.738 2.967 3.645 1.597 -7.1
Hunt & Reffert 2024 303.909 45.738 2.967 3.645 1.597 -3.413
Cavallo et al. 2024 303.549 45.581 2.967 – – –
Hunt & Reffert 2023 303.909 45.738 2.967 3.645 1.597 -3.413
Almeida et al. 2023 303.553 45.602 – – – –
He et al. 2022 304.44 46.787 2.928 3.533 1.893 –
Dias et al. 2021 303.557 45.535 2.952 3.614 1.599 -6.875
Cantat-Gaudin et al. 2020 303.482 45.574 2.945 3.573 1.605 –
Zhong et al. 2020 303.482 45.574 – 3.573 1.605 -13.003
Cantat-Gaudin & Anders 2020 303.482 45.574 2.945 3.573 1.605 –
Soubiran et al. 2018 303.482 45.574 – – – -6.91
Cantat-Gaudin et al. 2018 303.482 45.574 2.945 3.573 1.605 –
Roser et al. 2016 303.67 45.59 – 3.41 2.22 –

💡 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– 0.335 0.11 0.51 40 0.052 158 0.41 –
Yan et al. 2026 – – – 41 – – – –
Malhotra et al. 2026 0.33 0.03 – 64 0.105 – – –
Liu et al. 2025 0.38 0.07 – 40 – – – –
Li et al. 2025 0.36 0.16 – 43 0.153 – – –
Almeida et al. 2025 0.33 0.21 – 52 – 180 – –
Alfonso et al. 2024 0.33 0.01 – 33 0.013 – – –
Zhang et al. 2024 – – – – -0.032(1) – – –
Swiggum et al. 2024 0.33 – – 23 – 136 – –
Hunt & Reffert 2024 0.33 0.09 0.51 23 – 110(1) – –
Cavallo et al. 2024 0.35 0.51 – 21 0.040 – – –
Hunt & Reffert 2023 0.33 0.09 0.51 23 – – – –
Almeida et al. 2023 0.33 0.07 – 57 0.077 259(1) 0.41 –
He et al. 2022 – 0.50 – 40 – – – –
Dias et al. 2021 0.33 0.21 – 52 0.012 – – –
Cantat-Gaudin et al. 2020 0.33 0.01 – 35 – – – –
Kounkel et al. 2020 0.35 0.31 – 52 – – – –
Zhong et al. 2020 0.34(1) – – – 0.065 – – –
Cantat-Gaudin & Anders 2020 0.34 – – – – – – –
Soubiran et al. 2018 0.34 – – – – – – –
Cantat-Gaudin et al. 2018 0.34 – – – – – – –
Roser et al. 2016 0.35 0.13 – 50 – – – –

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

Cluster % RA DEC Plx pmRA pmDE Rv UTI
OCSN 256 89.7 303.59 45.59 2.96 3.63 1.56 -7.39 0.01
LISC-III 3723 75.0 304.16 46.65 2.92 3.51 1.72 -7.45 0.2
OCSN 23 11.8 305.13 48.62 2.86 3.16 1.97 -7.7 0.29

💡 Note: The % column shows the percentage of members that RSG5 shares with each listed object.

Visualization
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RSG5 UCC
RSG5 HUNT23
RSG5 CANTAT20
Galactocentric position diagram