Theia 1040
0.27
UTI
0.26
CN
0.1
Cdens
0.75
CC3
0.13
Clit
1.0
Cdup
Nm (P>50%)
26
Core radius and density
2.2 [pc], 0.5 [pc-2]
- CN 0.26 Poorly populated
- Cdens 0.1 Very loose
- CC3 0.75 High 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 1040 is a poorly populated, very loose object of high C3 quality. Its parallax locates it at a close distance, above 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 | 69.397 | 56.585 | 1.585 | -1.811 | -5.645 | -16.09 |
| Hu & Soubiran | 2025 | 69.134 | 56.719 | â | â | â | â |
| Yang et al. | 2025 | 69.443 | 56.514 | â | â | â | â |
| Zhang et al. | 2024 | 69.443 | 56.514 | â | â | â | â |
| Cavallo et al. | 2024 | 69.134 | 56.719 | 1.584 | â | â | â |
| Hunt & Reffert | 2023 | 69.443 | 56.514 | 1.579 | -1.794 | -5.647 | -15.001 |
| Kounkel & Covey | 2019 | 69.135 | 56.515 | 1.666 | â | â | -14.874 |
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 | 0.6 | 0.67 | 0.51 | 650 | -0.030 | â | â | â |
| Hu & Soubiran | 2025 | â | â | â | â | -0.070(5) | â | â | â |
| Yang et al. | 2025 | â | â | â | 603 | -0.010(3) | â | â | â |
| Zhang et al. | 2024 | â | â | â | â | -0.050(1) | â | â | â |
| Cavallo et al. | 2024 | 0.61 | 0.67 | â | 708 | 0.330 | â | â | â |
| Hunt & Reffert | 2023 | 0.59 | 0.64 | 0.51 | 596 | â | â | â | â |
| Kounkel & Covey | 2019 | 0.60 | 0.67 | â | 696 | 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 P258, along with Alessi_2.
Cavallo et al. (2024)
Gold sample.
Hunt & Reffert (2024)
Classified as moving group. CMD class: 0.96 (50th percentile).
Hunt & Reffert (2023)
Classified as open cluster. CMD class: 0.96 (50th percentile).