Theia 172
0.49
UTI
0.84
CN
0.3
Cdens
1.0
CC3
0.16
Clit
1.0
Cdup
Nm (P>50%)
330
Core radius and density
4.5 [pc], 1.5 [pc-2]
- CN 0.84 Rich
- Cdens 0.3 Loose
- CC3 1.0 Very 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 172 is a rich, loose object of very high C3 quality. Its parallax locates it at a very 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.
Note: This object shares a large percentage of members with 4 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 | 110.209 | 3.703 | 2.125 | -6.503 | -5.118 | 13.557 |
| Yan et al. | 2026 | 110.277 | 4.082 | 2.113 | -6.459 | -5.036 | â |
| Yang et al. | 2025 | 110.277 | 4.082 | â | â | â | â |
| Zhang et al. | 2024 | 110.277 | 4.082 | â | â | â | â |
| Hunt & Reffert | 2024 | 110.277 | 4.082 | 2.113 | -6.459 | -5.036 | 15.359 |
| Cavallo et al. | 2024 | 110.091 | 3.188 | 2.12 | â | â | â |
| Hunt & Reffert | 2023 | 110.277 | 4.082 | 2.113 | -6.459 | -5.036 | 15.359 |
| Kounkel & Covey | 2019 | 109.936 | 2.85 | 2.041 | â | â | 3.785 |
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 | 0.47 | 0.175 | 0.54 | 120 | -0.002 | 156 | â | â |
| Yan et al. | 2026 | â | â | â | 121 | â | â | â | â |
| Yang et al. | 2025 | â | â | â | 120 | -0.150(3) | â | â | â |
| Zhang et al. | 2024 | â | â | â | â | -0.002(1) | â | â | â |
| Hunt & Reffert | 2024 | 0.45 | 0.09 | 0.54 | 121 | â | 156(1) | â | â |
| Cavallo et al. | 2024 | 0.49 | 0.28 | â | 76 | 0.190 | â | â | â |
| Hunt & Reffert | 2023 | 0.45 | 0.09 | 0.54 | 122 | â | â | â | â |
| Kounkel & Covey | 2019 | 0.49 | 0.26 | â | 70 | 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=4, with probability of formation through binary evolution >=0.5 N=3.
Palma et al. (2025)
Part of multiple system G127, along with Theia_383 and HSC_1707.
Cavallo et al. (2024)
Gold sample.
Hunt & Reffert (2024)
Classified as open cluster. CMD class: 1.00 (50th percentile).
Hunt & Reffert (2023)
Classified as open cluster. CMD class: 1.00 (50th percentile).