Kepler-90 i
Astrophysical Synthesis & Habitability Characterization
Kepler-90 i is a confirmed super-earth exoplanet orbiting the star KOI-351, located approximately 2766.6 light-years (848.25 parsecs) from the Solar System. First announced in 2017 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0088% across the stellar disk), this world measures 1.32 Earth radii and has a measured mass of 2.3 Earth masses. Combining its mass and radius yields a mean bulk density of 5.51 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.32 g⊕ (12.94 m/s²), and an escape velocity of 14.8 km/s.
In its orbital architecture around KOI-351, Kepler-90 i completes one full revolution every 14.449 Earth days at a semi-major axis of 0.120138 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 90.5 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 709 K (+436°C / +817°F) and receiving 128.58 S⊕ (~174,996 W/m²), Kepler-90 i orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star KOI-351 is classified as a stellar host with an effective photospheric temperature of 6,015 K, a radius of 1.29 R☉, a mass of 1.12 M☉, an estimated bolometric luminosity of 1.954 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.53 Gyr and a metallicity of [Fe/H] = 0.098 dex (metal-rich relative to the Sun). From Earth, KOI-351 shines at apparent V-band magnitude 13.883 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The KOI-351 system is a multi-planet architecture hosting 8 confirmed worlds, with Kepler-90 i sharing its stellar neighborhood alongside KOI-351 b, KOI-351 c, KOI-351 d, KOI-351 e, KOI-351 f, KOI-351 g, KOI-351 h.
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 | KOI-351 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,015 K |
| Stellar Radius | 1.2900 R☉ |
| Stellar Mass | 1.1200 M☉ |
| Bolometric Luminosity | 1.954 L☉ |
| Metallicity [Fe/H] | 0.098 dex |
| Stellar Age | 0.530 Gyr |
| Apparent Magnitude | V: 13.883 · G: 13.740 |
| System Architecture | 1 Star, 8 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.120138 AU |
| Orbital Period | 14.449 days |
| Mean Orbital Velocity | 90.5 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.2000° |
| Mean Bulk Density | 5.51 g/cm³ (14.8 km/s vesc) |
| Insolation Flux | 128.5790 S⊕ (~174,996 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2766.600 LY (848.254 pc) |