HSC 1991
0.12
UTI
0.25
CN
0.12
Cdens
0.25
CC3
0.0
Clit
1.0
Cdup
Stellar density (N50/rad)
0.6 [N/pc2]
- CN 0.25 Poorly populated
- Cdens 0.12 Very loose
- CC3 0.25 Low quality
- Clit 0.0 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
HSC 1991 is a poorly populated, very loose object of low 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, intermediate-age cluster, but with a large variance across recent sources for the age parameter (see Parameters). It was recently reported 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 | 106.599 | -39.228 | 6.583 | -3.471 | -6.797 | 28.258 |
| Hu & Soubiran | 2025 | 106.05 | -38.948 | â | â | â | â |
| Cavallo et al. | 2024 | 106.05 | -38.948 | 6.697 | â | â | â |
| Hunt & Reffert | 2023 | 105.128 | -36.586 | 6.653 | -3.163 | -6.97 | 22.071 |
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 | 0.15 | 0.175 | 0.37 | 774 | 0.250 | â | â | â |
| Cavallo et al. | 2024 | 0.15 | 0.30 | â | 1413 | 0.250 | â | â | â |
| Hunt & Reffert | 2023 | 0.15 | 0.05 | 0.37 | 134 | â | â | â | â |
Cavallo et al. (2024)
Gold sample.
Hunt & Reffert (2024)
Classified as a moving group.