Kepler-1854 b
Astrophysical Synthesis & Habitability Characterization
Kepler-1854 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1854, located approximately 1380.8 light-years (423.35 parsecs) from the Solar System. First announced in 2021 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0976% across the stellar disk), this world measures 2.587 Earth radii and has a measured mass of 7.21 Earth masses. Combining its mass and radius yields a mean bulk density of 2.3 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.08 g⊕ (10.59 m/s²), and an escape velocity of 18.7 km/s.
In its orbital architecture around Kepler-1854, Kepler-1854 b completes one full revolution every 39.831 Earth days at a semi-major axis of 0.20894 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 57.1 km/s (compared to Earth's 29.8 km/s). The orbit is modeled as circular (e = 0.00), maintaining a constant stellar distance throughout its year.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 420 K (+147°C / +297°F) and receiving 7.33 S⊕ (~9,976 W/m²), Kepler-1854 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-1854 is classified as a stellar host with an effective photospheric temperature of 5,026 K, a radius of 0.759 R☉, a mass of 0.8 M☉, an estimated bolometric luminosity of 0.33 L☉. Stellar evolution modeling indicates an estimated stellar age of 12.88 Gyr and a metallicity of [Fe/H] = 0 dex (near-solar heavy-element abundance). From Earth, Kepler-1854 shines at apparent V-band magnitude 14.381 (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-1854 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,026 K |
| Stellar Radius | 0.7590 R☉ |
| Stellar Mass | 0.8000 M☉ |
| Bolometric Luminosity | 0.33 L☉ |
| Metallicity [Fe/H] | 0.000 dex |
| Stellar Age | 12.880 Gyr |
| Apparent Magnitude | V: 14.381 · G: 14.107 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.208940 AU |
| Orbital Period | 39.831 days |
| Mean Orbital Velocity | 57.1 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.8900° |
| Mean Bulk Density | 2.3 g/cm³ (18.7 km/s vesc) |
| Insolation Flux | 7.3300 S⊕ (~9,976 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1380.800 LY (423.348 pc) |