UBC 251
0.51
UTI
0.66
CN
0.26
Cdens
0.75
CC3
0.52
Clit
0.94
Cdup
Nm (P>50%)
83
Core radius and density
2.6 [pc], 1.3 [pc-2]
- CN 0.66 Moderately populated
- Cdens 0.26 Loose
- CC3 0.75 High quality
- Clit 0.52 Moderately studied
- Cdup 0.94 Very likely 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 251 is a moderately populated, loose object of high C3 quality. Its parallax locates it at a relatively close distance, near 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 absorption and metallicity parameters (see Parameters). It is moderately studied in the literature.
Note: This is very likely a unique object, which shares a very small percentage of members with at least one previously reported entry. See table with shared members information.
Data
| Reference | Year | RA [deg] | DEC [deg] | Plx [mas] | pmRA [mas/yr] | pmDE [mas/yr] | Rv [km/s] |
|---|---|---|---|---|---|---|---|
| UCC | 99999â | 140.456 | -51.259 | 0.514 | -4.957 | 4.452 | 35.729 |
| Li et al. | 2026 | 140.44 | -51.28 | â | â | â | â |
| Almeida et al. | 2025 | 140.43 | -51.244 | â | â | â | â |
| Hunt & Reffert | 2024 | 140.453 | -51.249 | 0.538 | -4.937 | 4.471 | 28.365 |
| Cavallo et al. | 2024 | 140.429 | -51.251 | 0.533 | â | â | â |
| Hunt & Reffert | 2023 | 140.453 | -51.249 | 0.538 | -4.937 | 4.471 | 28.365 |
| Almeida et al. | 2023 | 140.434 | -51.219 | â | â | â | â |
| Dias et al. | 2021 | 140.43 | -51.244 | 0.464 | -4.995 | 4.428 | â |
| Cantat-Gaudin et al. | 2020 | 140.447 | -51.252 | 0.484 | -4.997 | 4.436 | â |
| Castro-Ginard et al. | 2020 | 140.426 | -51.27 | 0.486 | -5.009 | 4.432 | 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 | 1.8 | 1.48 | 0.47 | 72 | 0.147 | 379 | 0.5 | â |
| Liu et al. | 2025 | 2.91 | 0.46 | â | 110 | â | â | â | â |
| Almeida et al. | 2025 | 1.96 | 1.48 | â | 72 | â | 379 | â | â |
| Hunt & Reffert | 2024 | 1.76 | 1.32 | 0.47 | 66 | â | 357(1) | â | â |
| Cavallo et al. | 2024 | 1.67 | 1.59 | â | 62 | -0.020 | â | â | â |
| Hunt & Reffert | 2023 | 1.76 | 1.31 | 0.47 | 66 | â | â | â | â |
| Almeida et al. | 2023 | 1.79 | 1.55 | â | 76 | 0.147 | 478(1) | 0.50 | â |
| Dias et al. | 2021 | 1.96 | 1.48 | â | 72 | 0.376 | â | â | â |
| Cantat-Gaudin et al. | 2020 | 1.86 | 1.27 | â | 93 | â | â | â | â |
| Kounkel et al. | 2020 | 1.80 | 1.87 | â | 36 | 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=54+/-62.2 [pc], r_c=0.51+/-0.0 [pc]; stars within r_t: N~111
Liu et al. (2025)
Classified as tidal capture (resonant trapping binary) 376 along with UBC_487.
Palma et al. (2025)
Classified as optical pair P602, along with UBC_487.
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).