Astronomical evidence
HD 128311 c was discovered from its host star's radial-velocity variations. A later combination with Hubble astrometry constrained orbital inclination and a true mass of about 3.789 Jupiter masses, with +0.924/−0.432 reported errors. [2] The saved catalog distinguishes this value from a minimum mass and records an orbital period near 921.538 days. [1] These observations do not resolve rings or weather. The quiet lake and the ringed appearance belong entirely to the artistic reconstruction.
The illustrated viewpoint
Distant broad-shouldered alien in an ochre cloak, viewed from behind in meditation. The tranquil lakeshore of an invented moon of HD 128311 c. The moon, lake, atmosphere, warrior, planet color and rings are all invented. The rings are a compositional hypothesis, not a detection. Their ellipse, shadows and occultation should remain coherent, but no particle distribution or satellite dynamics are calculated.
The moon, lake, atmosphere, warrior, planet color and rings are all invented. The rings are a compositional hypothesis, not a detection. Their ellipse, shadows and occultation should remain coherent, but no particle distribution or satellite dynamics are calculated. All beings and cultures are fictional. Apparent sizes, phases and exposure are artistic, not a calibrated sky simulation. Cosmic connection is a visual theme, not an observed biological mechanism.
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 |