Theia 558
0.46
UTI
0.5
CN
0.59
Cdens
0.5
CC3
0.35
Clit
1.0
Cdup
Stellar density (N50/rad)
2.9 [N/pc2]
- CN 0.5 Moderately populated
- Cdens 0.59 Moderately dense
- CC3 0.5 Intermediate quality
- Clit 0.35 Poorly 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
Theia 558 is a moderately populated, moderately dense object of intermediate C3 quality. Its parallax locates it at a 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 absorption and age parameters (see Parameters). It is poorly studied in the literature.
Data
| Reference | Year | RA [deg] | DEC [deg] | Plx [mas] | pmRA [mas/yr] | pmDE [mas/yr] | Rv [km/s] |
|---|---|---|---|---|---|---|---|
| UCC | 99999â | 95.945 | 3.673 | 1.407 | -0.692 | -1.813 | 0.459 |
| Zhang et al. | 2024 | 95.905 | 3.67 | â | â | â | â |
| Hunt & Reffert | 2024 | 95.905 | 3.67 | 1.41 | -0.685 | -1.827 | -1.075 |
| Cavallo et al. | 2024 | 95.977 | 3.72 | 1.409 | â | â | â |
| Hunt & Reffert | 2023 | 95.905 | 3.67 | 1.41 | -0.685 | -1.827 | -1.075 |
| He et al. | 2022 | 95.953 | 3.644 | 1.406 | -0.651 | -1.81 | 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 | 0.66 | 0.82 | 2.11 | 242 | -0.135 | 72 | â | â |
| Liu et al. | 2025 | 1.61 | 0.41 | â | 31 | â | â | â | â |
| Zhang et al. | 2024 | â | â | â | â | -0.019(1) | â | â | â |
| Hunt & Reffert | 2024 | â | â | â | â | â | 72(1) | â | â |
| Cavallo et al. | 2024 | 0.66 | 0.99 | â | 316 | -0.250 | â | â | â |
| Hunt & Reffert | 2023 | 0.66 | 0.65 | 2.11 | 202 | â | â | â | â |
| He et al. | 2022 | â | 1.60 | â | 282 | â | â | â | â |
(N): Indicates that there are N extra values assigned to this parameter in the corresponding reference.
Liu et al. (2025)
Classified as primordial binary cluster 307 along with OC_0343.
Palma et al. (2025)
Classified as optical pair P559, along with OC_0343.
Cavallo et al. (2024)
Gold sample.