Theia 844
0.26
UTI
0.5
CN
0.04
Cdens
0.5
CC3
0.13
Clit
1.0
Cdup
Nm (P>50%)
50
Core radius and density
5.6 [pc], 0.2 [pc-2]
- CN 0.5 Moderately populated
- Cdens 0.04 Very loose
- CC3 0.5 Intermediate quality
- Clit 0.13 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
Theia 844 is a moderately populated, very loose 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 metallicity parameter (see Parameters). It is rarely studied in the literature.
â ī¸ Warning: the low UTI value and no obvious signs of duplication (Cdup=1.0) indicate that this is quite probably an asterism, moving group, or artifact, and not a real open cluster.
Data
| Reference | Year | RA [deg] | DEC [deg] | Plx [mas] | pmRA [mas/yr] | pmDE [mas/yr] | Rv [km/s] |
|---|---|---|---|---|---|---|---|
| UCC | 99999â | 310.531 | 42.288 | 1.526 | 1.538 | -8.752 | 8.94 |
| Hu & Soubiran | 2025 | 310.431 | 42.304 | â | â | â | â |
| Yang et al. | 2025 | 310.109 | 41.922 | â | â | â | â |
| Zhang et al. | 2024 | 310.109 | 41.922 | â | â | â | â |
| Cavallo et al. | 2024 | 310.431 | 42.304 | 1.525 | â | â | â |
| Hunt & Reffert | 2023 | 310.109 | 41.922 | 1.522 | 1.529 | -8.699 | 6.601 |
| Kounkel & Covey | 2019 | 310.545 | 42.53 | 1.592 | â | â | 24.15 |
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 | 0.63 | 0.46 | 0.49 | 646 | -0.026 | â | â | â |
| Hu & Soubiran | 2025 | â | â | â | â | -0.220(5) | â | â | â |
| Yang et al. | 2025 | â | â | â | 646 | -0.060(3) | â | â | â |
| Zhang et al. | 2024 | â | â | â | â | 0.008(1) | â | â | â |
| Cavallo et al. | 2024 | 0.61 | 0.46 | â | 912 | 0.210 | â | â | â |
| Hunt & Reffert | 2023 | 0.63 | 0.24 | 0.49 | 646 | â | â | â | â |
| Kounkel & Covey | 2019 | 0.63 | 0.70 | â | 436 | â | â | â | â |
(N): Indicates that there are N extra values assigned to this parameter in the corresponding reference.
Palma et al. (2025)
Classified as optical pair P589, along with UPK_120.
Cavallo et al. (2024)
Gold sample.
Hunt & Reffert (2024)
Classified as moving group. CMD class: 0.95 (50th percentile).
Hunt & Reffert (2023)
Classified as open cluster. CMD class: 0.95 (50th percentile).