Astronomical evidence
HD 128311 c orbits HD 128311. The saved catalog gives an orbital period of 921.538 ± 1.15 days. Its discovery method is recorded as radial velocity. These quantities describe the real astronomical setting behind the illustration. HD 128311 c was discovered through radial velocities. The saved composite entry combines measurements and modeling from several sources; its listed radius is explicitly calculated. A calculated radius may be useful for a schematic comparison, but it is not a detected planetary silhouette or a resolved disk. The catalog radius of 13 Earth radii is calculated, not directly measured. The mass entry is 1204.25787 (+293.675/−137.303) Earth masses. The source papers and full table retain the provenance of each parameter.
The illustrated viewpoint
The moon and planetary rings in the artwork are invented. The mass of a known giant does not establish that it possesses the particular satellite or ring architecture shown.
The moon and planetary rings in the artwork are invented. The mass of a known giant does not establish that it possesses the particular satellite or ring architecture shown. All depicted life and technology are fictional.
Catalog measurements & sources
Host: HD 128311. Snapshot: 25 September 2026. Errors, limits and source provenance are retained. Calculated values and model estimates are not direct measurements. Unknown is not zero; equilibrium temperature is not surface temperature.
| Quantity / unit | Value / reported errors | Source |
|---|---|---|
| Radius · Earth radii | 13 | Calculated Value |
| Mass · Earth masses | 1204.26 (+293.675 / -137.303) | McArthur et al. 2014 |
| Density · g/cm³ | 3.01 | Calculated Value |
| Orbital period · days | 921.538 (+1.15 / -1.15) | McArthur et al. 2014 |
| Orbital semimajor axis · AU | 1.74 (+0.01 / -0.01) | McArthur et al. 2014 |
| Eccentricity | 0.159 (+0.006 / -0.006) | McArthur et al. 2014 |
| Inclination · degrees | 55.95 (+14.553 / -14.553) | McArthur et al. 2014 |
| Irradiation · Earth flux | 0.1017 (+0.0012 / -0.0012) | Calculated Value |
| Equilibrium temperature · K | 158.23 (+2.55 / -2.55) | Calculated Value |
| Stellar effective temperature · K | 4965 (+44 / -44) | Wittenmyer et al. 2009 |
| Stellar radius · Solar | 0.76 (+0.02 / -0.02) | McArthur et al. 2014 |
| Stellar mass · Solar | 0.828 (+0.008 / -0.012) | McArthur et al. 2014 |
| Stellar luminosity · log Solar | -0.5116 (+0.0007 / -0.0007) | Gaia DR2 |
| Stellar age · Gyr | ≤ 0.96 | McArthur et al. 2014 |
| Stellar metallicity · dex | 0.08 (+0.03 / -0.03) | Wittenmyer et al. 2009 |
| Distance · pc | 16.3292 (+0.0199 / -0.0198) | TICv8 |