UBC 531
0.53
UTI
0.41
CN
0.2
Cdens
1.0
CC3
0.52
Clit
1.0
Cdup
Nm (P>50%)
41
Core radius and density
2.2 [pc], 1.0 [pc-2]
- CN 0.41 Poorly populated
- Cdens 0.2 Very loose
- CC3 1.0 Very high quality
- Clit 0.52 Moderately studied
- Cdup 1.0 Unique
đĨ Members
đ Colab
đŦ Bayestar19
MOCA
đ CDS
đ Simbad
đ CDS (Îą, δ)
đ Simbad (Îą, δ)
MOCA
đ CDS
đ Simbad
đ CDS (Îą, δ)
đ Simbad (Îą, δ)
Overview
UBC 531 is a poorly populated, very loose object of very high C3 quality. Its parallax locates it at a moderate distance, below the mid-plane, affected by moderate extinction. It is catalogued as a near-solar metallicity, young cluster, but with a large variance across recent sources for the age and metallicity parameters (see Parameters). It is moderately studied in the literature.
Data
| Reference | Year | RA [deg] | DEC [deg] | Plx [mas] | pmRA [mas/yr] | pmDE [mas/yr] | Rv [km/s] |
|---|---|---|---|---|---|---|---|
| UCC | 99999â | 211.832 | -63.08 | 0.361 | -5.262 | -2.929 | -17.657 |
| Li et al. | 2026 | 211.77 | -63.06 | â | â | â | â |
| Li et al. | 2025 | 211.837 | -63.076 | 0.349 | -5.216 | -2.916 | â |
| Almeida et al. | 2025 | 211.814 | -63.061 | â | â | â | â |
| Hunt & Reffert | 2024 | 211.835 | -63.066 | 0.371 | -5.266 | -2.912 | -21.035 |
| Cavallo et al. | 2024 | 211.818 | -63.067 | 0.372 | â | â | â |
| Hunt & Reffert | 2023 | 211.835 | -63.066 | 0.371 | -5.266 | -2.912 | -21.035 |
| Dias et al. | 2021 | 211.814 | -63.061 | 0.353 | -5.207 | -2.91 | -23.635 |
| Cantat-Gaudin et al. | 2020 | 211.837 | -63.076 | 0.349 | -5.216 | -2.916 | â |
| Castro-Ginard et al. | 2020 | 211.801 | -63.072 | 0.358 | -5.223 | -2.926 | â |
đĄ 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 | 99999â | 2.44 | 1.82 | 0.5 | 30 | 0.254 | 377 | â | â |
| Liu et al. | 2025 | 4.45 | 0.62 | â | 72 | â | â | â | â |
| Li et al. | 2025 | 2.04 | 1.90 | â | 29 | -0.040 | â | â | â |
| Almeida et al. | 2025 | 2.60 | 2.01 | â | 14 | â | 337 | â | â |
| Hunt & Reffert | 2024 | 2.44 | 1.82 | 0.50 | 30 | â | 417(1) | â | â |
| Cavallo et al. | 2024 | 2.24 | 1.19 | â | 178 | 0.820 | â | â | â |
| Hunt & Reffert | 2023 | 2.44 | 1.82 | 0.50 | 30 | â | â | â | â |
| Dias et al. | 2021 | 2.60 | 2.01 | â | 14 | 0.254 | â | â | â |
| Cantat-Gaudin et al. | 2020 | 2.69 | 1.64 | â | 81 | â | â | â | â |
| Kounkel et al. | 2020 | 2.04 | 2.35 | â | 55 | â | â | â | â |
(N): Indicates that there are N extra values assigned to this parameter in the corresponding reference.
Li et al. (2026)
Tidal & Core radii: r_t=70+/-77.3 [pc], r_c=0.2+/-0.0 [pc]; stars within r_t: N~76
Liu et al. (2025)
Classified as primordial binary cluster 362 along with Theia_2179.
Palma et al. (2025)
Classified as genetic pair P244, along with Theia_2179.
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: 0.99 (50th percentile).
Hunt & Reffert (2023)
Classified as open cluster. CMD class: 0.99 (50th percentile).