UBC 550
0.54
UTI
0.75
CN
0.54
Cdens
1.0
CC3
0.19
Clit
1.0
Cdup
Nm (P>50%)
111
Core radius and density
2.1 [pc], 2.7 [pc-2]
- CN 0.75 Rich
- Cdens 0.54 Moderately dense
- CC3 1.0 Very high quality
- Clit 0.19 Rarely 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 550 is a rich, moderately dense object of very high C3 quality. Its parallax locates it at a moderate 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 age parameter (see Parameters). It is rarely studied in the literature.
Note: This object shares a small percentage of members with a later 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 | 252.627 | -45.066 | 0.384 | -2.572 | -4.147 | -14.353 |
| Almeida et al. | 2025 | 252.634 | -45.062 | â | â | â | â |
| Hunt & Reffert | 2024 | 252.622 | -45.08 | 0.392 | -2.574 | -4.111 | -47.495 |
| Cavallo et al. | 2024 | 252.64 | -45.07 | 0.392 | â | â | â |
| Hunt & Reffert | 2023 | 252.622 | -45.08 | 0.392 | -2.574 | -4.111 | -47.495 |
| Dias et al. | 2021 | 252.634 | -45.062 | 0.361 | -2.546 | -4.108 | â |
| Cantat-Gaudin et al. | 2020 | 252.65 | -45.07 | 0.37 | -2.564 | -4.136 | â |
| Castro-Ginard et al. | 2020 | 252.644 | -45.066 | 0.369 | -2.558 | -4.123 | 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 | 2.49 | 2.7 | 2.08 | 74 | 0.483 | 900 | â | â |
| Almeida et al. | 2025 | 2.49 | 2.62 | â | 13 | â | 697 | â | â |
| Hunt & Reffert | 2024 | 2.30 | 2.82 | 2.08 | 143 | â | 1104(1) | â | â |
| Cavallo et al. | 2024 | 2.34 | 2.70 | â | 282 | 0.610 | â | â | â |
| Hunt & Reffert | 2023 | 2.30 | 2.82 | 2.08 | 144 | â | â | â | â |
| Dias et al. | 2021 | 2.49 | 2.62 | â | 13 | 0.356 | â | â | â |
| Cantat-Gaudin et al. | 2020 | 2.59 | 2.42 | â | 47 | â | â | â | â |
| Kounkel et al. | 2020 | 2.51 | 3.06 | â | 74 | â | â | â | â |
(N): Indicates that there are N extra values assigned to this parameter in the corresponding reference.
Palma et al. (2025)
Part of multiple system G255, along with UBC_1557, UBC_321 and UBC_1558.
Almeida et al. (2025)
Mass determination: good fit. Isochrone match: intermediate fit.
Cavallo et al. (2024)
Gold sample.
Hunt & Reffert (2024)
Classified as open cluster. CMD class: 0.95 (50th percentile).
Hunt & Reffert (2023)
Classified as open cluster. CMD class: 0.95 (50th percentile).