Kepler-450 d
Astrophysical Synthesis & Habitability Characterization
Kepler-450 d is a confirmed terrestrial exoplanet orbiting the star Kepler-450, located approximately 1487.2 light-years (455.98 parsecs) from the Solar System. First announced in 2015 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0022% across the stellar disk), this world measures 0.837 Earth radii and has a measured mass of 17.6 Earth masses. Combining its mass and radius yields a mean bulk density of 165.5 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 25.12 g⊕ (246.34 m/s²), and an escape velocity of 51.3 km/s.
In its orbital architecture around Kepler-450, Kepler-450 d completes one full revolution every 7.515 Earth days at a semi-major axis of 0.0827 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 119.7 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.14 carries the world between 0.0711 AU at periapsis and 0.0943 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1199 K (+926°C / +1699°F) and receiving 557.21 S⊕ (~758,356 W/m²), Kepler-450 d orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-450 is classified as a stellar host with an effective photospheric temperature of 6,197 K, a radius of 1.6416 R☉, a mass of 1.19 M☉, an estimated bolometric luminosity of 3.566 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.57 Gyr and a metallicity of [Fe/H] = 0.128 dex (metal-rich relative to the Sun). From Earth, Kepler-450 shines at apparent V-band magnitude 11.991 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-450 system is a multi-planet architecture hosting 3 confirmed worlds, with Kepler-450 d sharing its stellar neighborhood alongside Kepler-450 c, Kepler-450 b.
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-450 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,197 K |
| Stellar Radius | 1.6416 R☉ |
| Stellar Mass | 1.1900 M☉ |
| Bolometric Luminosity | 3.566 L☉ |
| Metallicity [Fe/H] | 0.128 dex |
| Stellar Age | 2.570 Gyr |
| Apparent Magnitude | V: 11.991 · G: 11.653 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.082700 AU |
| Orbital Period | 7.515 days |
| Mean Orbital Velocity | 119.7 km/s |
| Orbital Eccentricity (e) | 0.14000 |
| Orbital Inclination (i) | 87.9100° |
| Mean Bulk Density | 165.5 g/cm³ (51.3 km/s vesc) |
| Insolation Flux | 557.2050 S⊕ (~758,356 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1487.200 LY (455.982 pc) |