Astronomical evidence
Ross 128 b was detected through repeated changes in its star’s radial velocity. The planet and star orbit their shared center of mass; the star’s motion toward and away from Earth shifts its spectral lines. The saved catalog gives an orbital period of 9.8658 ± 0.0070 days. The quoted mass, 1.40 ± 0.21 Earth masses, is a minimum mass: m sin i. Without knowing the orbital inclination, this signal alone does not establish the true mass. The listed radius of 1.11 Earth radii is calculated, rather than measured from a transit. The discovery study identified Ross 128 as a relatively quiet nearby red dwarf. Lower observed stellar activity helps distinguish small orbital signals from stellar variability, and matters when considering the radiation a planet receives. It does not demonstrate a stable surface climate or a surviving atmosphere.
The illustrated viewpoint
Tripod carapace with ventral sensory web in a still, inward-folded meditative pose. A fictional twilight plateau on an indirectly detected planet. The high plateau, mist and sunset are fictional local scenery. Their scale and colors are artistic choices; the stellar-motion measurements do not supply a map of this world.
The high plateau, mist and sunset are fictional local scenery. Their scale and colors are artistic choices; the stellar-motion measurements do not supply a map of this world. All depicted life is fictional. The visual connection to the cosmos is an artistic theme, not a claimed biological mechanism.
Catalog measurements & sources
Host: Ross 128. 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 | 1.11 | Calculated Value |
| Mass · Earth masses | 1.4 (+0.21 / -0.21) | Bonfils et al. 2018 |
| Density · g/cm³ | 5.63 | Calculated Value |
| Orbital period · days | 9.8658 (+0.007 / -0.007) | Bonfils et al. 2018 |
| Orbital semimajor axis · AU | 0.0496 (+0.0017 / -0.0017) | Bonfils et al. 2018 |
| Eccentricity | 0.116 (+0.097 / -0.097) | Bonfils et al. 2018 |
| Inclination · degrees | Unknown | Not supplied |
| Irradiation · Earth flux | 1.38 | Bonfils et al. 2018 |
| Equilibrium temperature · K | 301 | Bonfils et al. 2018 |
| Stellar effective temperature · K | 3192 (+60 / -60) | Bonfils et al. 2018 |
| Stellar radius · Solar | 0.1967 (+0.0077 / -0.0077) | Bonfils et al. 2018 |
| Stellar mass · Solar | 0.168 (+0.017 / -0.017) | Bonfils et al. 2018 |
| Stellar luminosity · log Solar | -2.44129 (+0.04444 / -0.04951) | Bonfils et al. 2018 |
| Stellar age · Gyr | ≥ 5 | Bonfils et al. 2018 |
| Stellar metallicity · dex | -0.02 (+0.08 / -0.08) | Bonfils et al. 2018 |
| Distance · pc | 3.37454 (+0.000805 / -0.000805) | TICv8 |