Kepler-1928 b
Astrophysical Synthesis & Habitability Characterization
Kepler-1928 b is a confirmed super-earth exoplanet orbiting the star Kepler-1928, located approximately 1064.4 light-years (326.36 parsecs) from the Solar System. First announced in 2021 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0394% across the stellar disk), this world measures 1.992 Earth radii and has a measured mass of 4.63 Earth masses. Combining its mass and radius yields a mean bulk density of 3.23 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.17 g⊕ (11.47 m/s²), and an escape velocity of 17.1 km/s.
In its orbital architecture around Kepler-1928, Kepler-1928 b completes one full revolution every 19.578 Earth days at a semi-major axis of 0.194 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 107.8 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.43, swinging from 0.1106 AU at periapsis out to 0.2774 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 621 K (+348°C / +658°F) and receiving 37.80 S⊕ (~51,446 W/m²), Kepler-1928 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-1928 is classified as a stellar host with an effective photospheric temperature of 5,720 K, a radius of 0.92 R☉, a mass of 1.01 M☉, an estimated bolometric luminosity of 0.813 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.105 Gyr and a metallicity of [Fe/H] = 0.12 dex (metal-rich relative to the Sun). From Earth, Kepler-1928 shines at apparent V-band magnitude 12.679 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.
Methodology: Computed using the Schulze-Makuch et al. (2011) weighted metric comparing physical interior (radius, estimated density) and surface thermal regime (escape velocity, equilibrium temperature).
Discovery Facility: Kepler · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | Kepler-1928 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,720 K |
| Stellar Radius | 0.9200 R☉ |
| Stellar Mass | 1.0100 M☉ |
| Bolometric Luminosity | 0.813 L☉ |
| Metallicity [Fe/H] | 0.120 dex |
| Stellar Age | 0.105 Gyr |
| Apparent Magnitude | V: 12.679 · G: 12.618 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.194000 AU |
| Orbital Period | 19.578 days |
| Mean Orbital Velocity | 107.8 km/s |
| Orbital Eccentricity (e) | 0.43000 |
| Orbital Inclination (i) | 88.9200° |
| Mean Bulk Density | 3.23 g/cm³ (17.1 km/s vesc) |
| Insolation Flux | 37.8000 S⊕ (~51,446 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1064.400 LY (326.362 pc) |