Hogg 21
(MWSC 2455)
0.83
UTI
0.76
CN
0.86
Cdens
1.0
CC3
0.77
Clit
1.0
Cdup
Nm (P>50%)
133
Core radius and density
1.4 [pc], 4.3 [pc-2]
- CN 0.76 Rich
- Cdens 0.86 Dense
- CC3 1.0 Very high quality
- Clit 0.77 Well-studied
- Cdup 1.0 Unique
π₯ Members
π Colab
π¬ Bayestar19
MOCA
π CDS
π Simbad
π CDS (Ξ±, Ξ΄)
π Simbad (Ξ±, Ξ΄)
MOCA
π CDS
π Simbad
π CDS (Ξ±, Ξ΄)
π Simbad (Ξ±, Ξ΄)
Overview
Hogg 21 is a rich, dense object of very high C3 quality. Its parallax locates it at a moderate distance, near the mid-plane, affected by moderate extinction. It is catalogued as a near-solar metallicity, young cluster, but with a large variance across recent sources for the age and mass parameters (see Parameters). It is well-studied in the literature.
Note: This object shares a very small percentage of members with a later reported entry. 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 | 99999β | 251.407 | -47.742 | 0.37 | -0.969 | -2.173 | -43.908 |
| Li et al. | 2025 | 251.414 | -47.747 | 0.366 | -0.937 | -2.206 | β |
| Almeida et al. | 2025 | 251.405 | -47.747 | β | β | β | β |
| Hunt & Reffert | 2024 | 251.414 | -47.744 | 0.375 | -1.009 | -2.147 | -46.992 |
| Cavallo et al. | 2024 | 251.413 | -47.749 | 0.374 | β | β | β |
| Hunt & Reffert | 2023 | 251.414 | -47.744 | 0.375 | -1.009 | -2.147 | -46.992 |
| Just et al. | 2023 | 251.389 | -47.747 | β | β | β | β |
| Dias et al. | 2022 | 251.404 | -47.739 | 0.369 | -1.004 | -2.121 | β |
| Dias et al. | 2021 | 251.405 | -47.747 | 0.377 | -0.96 | -2.207 | -2.217 |
| Cantat-Gaudin et al. | 2020 | 251.414 | -47.747 | 0.366 | -0.937 | -2.206 | β |
| SΓ‘nchez et al. | 2020 | 251.404 | -47.733 | β | -1.286 | -2.024 | β |
| Cantat-Gaudin & Anders | 2020 | 251.414 | -47.747 | 0.366 | -0.937 | -2.206 | β |
| Dias et al. | 2019 | 251.404 | -47.733 | 0.347 | -0.96 | -2.174 | -41.031 |
| Soubiran et al. | 2018 | 251.414 | -47.747 | β | β | β | -2.75 |
| Cantat-Gaudin et al. | 2018 | 251.414 | -47.747 | 0.366 | -0.937 | -2.206 | β |
| Dias et al. | 2018 | β | β | β | -1.02 | -2.75 | β |
| Dib et al. | 2018 | 251.4 | -47.747 | β | β | β | β |
| Sampedro et al. | 2017 | 251.404 | -47.733 | β | -0.34 | -3.03 | β |
| Joshi et al. | 2016 | 251.4 | -47.747 | β | β | β | β |
| Kharchenko et al. | 2016 | 251.389 | -47.747 | β | β | β | β |
| Dias et al. | 2014 | 251.404 | -47.733 | β | -0.35 | -3.07 | β |
| Kharchenko et al. | 2013 | 251.4 | -47.747 | β | -3.25 | -3.02 | β |
| Morales et al. | 2013 | 251.404 | -47.733 | β | β | β | β |
| Dias et al. | 2002 | 251.404 | -47.733 | β | -0.35 | -3.07 | β |
| Lynga | 1987 | 251.478 | -47.758 | β | β | β | β |
π‘ 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 | 99999β | 2.33 | 1.94 | 1.04 | 58 | 0.159 | 335 | β | β |
| Liu et al. | 2025 | 4.90 | 0.67 | β | 100 | β | β | β | β |
| Li et al. | 2025 | 2.06 | 1.68 | β | 343 | 0.060 | β | β | β |
| Almeida et al. | 2025 | 2.31 | 1.94 | β | 58 | β | 335 | β | β |
| Hunt & Reffert | 2024 | 2.57 | 1.82 | 1.04 | 94 | β | 772(1) | β | β |
| Cavallo et al. | 2024 | 2.23 | 2.00 | β | 141 | 0.040 | β | β | β |
| Hunt & Reffert | 2023 | 2.57 | 1.82 | 1.04 | 94 | β | β | β | β |
| Just et al. | 2023 | β | β | β | 28 | β | 69 | β | β |
| Dias et al. | 2022 | 2.33(1) | 1.92(1) | β | 93(1) | 0.159(1) | β | β | β |
| Dias et al. | 2021 | 2.31 | 1.94 | β | 58 | 0.169 | β | β | β |
| Cantat-Gaudin et al. | 2020 | 2.70 | 1.54 | β | 89 | β | β | β | β |
| Kounkel et al. | 2020 | 2.47 | 2.16 | β | 107 | β | β | β | β |
| Cantat-Gaudin & Anders | 2020 | 2.53 | β | β | β | β | β | β | β |
| Dias et al. | 2019 | 2.64 | 1.58 | β | 42 | 0.180 | β | β | β |
| Soubiran et al. | 2018 | 2.53 | β | β | β | β | β | β | β |
| Cantat-Gaudin et al. | 2018 | 2.53 | β | β | β | β | β | β | β |
| Dib et al. | 2018 | 1.75 | β | β | 28 | β | β | β | β |
| Joshi et al. | 2016 | 1.75 | 2.30 | β | 28 | β | β | β | β |
| Kharchenko et al. | 2016 | 1.75 | 2.30 | β | 28 | β | β | β | β |
| Kharchenko et al. | 2013 | 1.75 | 2.30 | β | 28 | β | β | β | β |
| Dias et al. | 2002 | 1.75 | 2.30 | β | 28 | β | β | β | β |
(N): Indicates that there are N extra values assigned to this parameter in the corresponding reference.
Liu et al. (2025)
Classified as tidal capture (resonant trapping binary) 262 along with UBC_549.
Palma et al. (2025)
Classified as optical pair P399, along with UBC_1551.
Almeida et al. (2025)
Mass determination: intermediate fit. Isochrone match: good fit. Silver sample.
Cavallo et al. (2024)
Gold sample.
Hunt & Reffert (2024)
Classified as open cluster. CMD classes: 1.00 (50th percentile), true positive (human-assigned).
Hunt & Reffert (2023)
Classified as open cluster. CMD classes: 1.00 (50th percentile), true positive (human-assigned).
Hu et al. (2021)
Ellipticities (core, all): e_core=0.2572, e_all=0.0807.
Morales et al. (2013)
Classified as morphological type 'OC2' (totally exposed cluster without correlation with ATLASGAL emission). Morphological flag: exposed cluster, without submm emission, presence of emission related to PAH or warm dust.