Kepler-404 b
Astrophysical Synthesis & Habitability Characterization
Kepler-404 b is a confirmed super-earth exoplanet orbiting the star Kepler-404, located approximately 2650.1 light-years (812.52 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0173% across the stellar disk), this world measures 1.27 Earth radii and has a measured mass of 2.15 Earth masses. Combining its mass and radius yields a mean bulk density of 5.79 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.33 g⊕ (13.04 m/s²), and an escape velocity of 14.6 km/s.
In its orbital architecture around Kepler-404, Kepler-404 b completes one full revolution every 11.83 Earth days at a semi-major axis of 0.102 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 93.8 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 730 K (+457°C / +855°F) and receiving 44.53 S⊕ (~60,611 W/m²), Kepler-404 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-404 is classified as a stellar host with an effective photospheric temperature of 5,654 K, a radius of 0.884 R☉, a mass of 0.86 M☉, an estimated bolometric luminosity of 0.717 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.35 Gyr and a metallicity of [Fe/H] = -0.03 dex (near-solar heavy-element abundance). From Earth, Kepler-404 shines at apparent V-band magnitude 15.479 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-404 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-404 b sharing its stellar neighborhood alongside Kepler-404 c.
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-404 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,654 K |
| Stellar Radius | 0.8840 R☉ |
| Stellar Mass | 0.8600 M☉ |
| Bolometric Luminosity | 0.717 L☉ |
| Metallicity [Fe/H] | -0.030 dex |
| Stellar Age | 1.350 Gyr |
| Apparent Magnitude | V: 15.479 · G: 15.191 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.102000 AU |
| Orbital Period | 11.83 days |
| Mean Orbital Velocity | 93.8 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.3800° |
| Mean Bulk Density | 5.79 g/cm³ (14.6 km/s vesc) |
| Insolation Flux | 44.5340 S⊕ (~60,611 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2650.100 LY (812.524 pc) |