Theia 38
0.42
UTI
0.25
CN
0.8
Cdens
0.75
CC3
0.16
Clit
1.0
Cdup
Nm (P>50%)
25
Core radius and density
1.0 [pc], 4.0 [pc-2]
- CN 0.25 Poorly populated
- Cdens 0.8 Dense
- CC3 0.75 High quality
- Clit 0.16 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 38 is a poorly populated, dense object of high C3 quality. Its parallax locates it at a very close distance, near the mid-plane, affected by low extinction. It is catalogued as a near-solar metallicity, very young cluster (see Parameters). It is rarely studied in the literature.
Note: This object shares a large percentage of members with 2 later reported entries. 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 | 291.815 | 21.143 | 2.02 | 1.228 | -6.402 | 19.114 |
| Yan et al. | 2026 | 291.745 | 21.117 | 1.981 | 1.181 | -6.101 | â |
| Zhang et al. | 2024 | 291.745 | 21.117 | â | â | â | â |
| Swiggum et al. | 2024 | 291.745 | 21.117 | 1.981 | 1.181 | -6.101 | -10.154 |
| Hunt & Reffert | 2024 | 291.745 | 21.117 | 1.981 | 1.181 | -6.101 | -11.229 |
| Cavallo et al. | 2024 | 290.753 | 22.222 | 1.979 | â | â | â |
| Hunt & Reffert | 2023 | 291.745 | 21.117 | 1.981 | 1.181 | -6.101 | -11.229 |
| Kounkel & Covey | 2019 | 290.537 | 22.404 | 2.01 | â | â | 11.123 |
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 | 0.5 | 0.885 | 2.05 | 6 | -0.085 | 816 | â | â |
| Yan et al. | 2026 | â | â | â | 21 | â | â | â | â |
| Zhang et al. | 2024 | â | â | â | â | 0.030(1) | â | â | â |
| Swiggum et al. | 2024 | 0.50 | â | â | 6 | â | 1201 | â | â |
| Hunt & Reffert | 2024 | 0.49 | 0.77 | 2.05 | 6 | â | 430(1) | â | â |
| Cavallo et al. | 2024 | 0.53 | 1.53 | â | 4 | -0.200 | â | â | â |
| Hunt & Reffert | 2023 | 0.49 | 0.77 | 2.05 | 6 | â | â | â | â |
| Kounkel & Covey | 2019 | 0.50 | 1.00 | â | 13 | â | â | â | â |
(N): Indicates that there are N extra values assigned to this parameter in the corresponding reference.
Yan et al. (2026)
Number of WDs: expected from single-star evolution N=0, with probability of formation through binary evolution >=0.5 N=5.
Palma et al. (2025)
Classified as optical pair P580, along with Theia_738.
Cavallo et al. (2024)
Gold sample.
Hunt & Reffert (2024)
Classified as open cluster. CMD class: 0.86 (50th percentile).
Hunt & Reffert (2023)
Classified as open cluster. CMD class: 0.86 (50th percentile).