Kepler-44 b
Astrophysical Synthesis & Habitability Characterization
Kepler-44 b is a confirmed gas giant exoplanet orbiting the star Kepler-44, located approximately 3874.7 light-years (1188 parsecs) from the Solar System. First announced in 2011 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.6887% across the stellar disk), this world measures 12.22 Earth radii (1.09 Jupiter radii) and has a measured mass of 317.82 Earth masses (1 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.96 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 2.13 g⊕ (20.89 m/s²), and an escape velocity of 57 km/s.
In its orbital architecture around Kepler-44, Kepler-44 b completes one full revolution every 3.247 Earth days at a semi-major axis of 0.0446 AU (an ultra-close orbit less than one-seventh of Mercury's 0.387 AU distance from the Sun, where strong stellar tidal forces typically induce synchronous rotation). Its mean orbital velocity is approximately 149.4 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.066 carries the world between 0.0417 AU at periapsis and 0.0475 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1544 K (+1271°C / +2320°F) and receiving 1,109.22 S⊕ (~1,509,653 W/m²), Kepler-44 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-44 is classified as a solar-type yellow star of spectral type G2 IV with an effective photospheric temperature of 5,800 K, a radius of 1.35 R☉, a mass of 1.12 M☉, an estimated bolometric luminosity of 1.85 L☉. Stellar evolution modeling indicates an estimated stellar age of 5.8 Gyr and a metallicity of [Fe/H] = 0.15 dex (metal-rich relative to the Sun). From Earth, Kepler-44 shines at apparent V-band magnitude 14.803 (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-44 |
| Spectral Type | G2 IV |
| Effective Temp (Teff) | 5,800 K |
| Stellar Radius | 1.3500 R☉ |
| Stellar Mass | 1.1200 M☉ |
| Bolometric Luminosity | 1.85 L☉ |
| Metallicity [Fe/H] | 0.150 dex |
| Stellar Age | 5.800 Gyr |
| Apparent Magnitude | V: 14.803 · G: 14.690 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.044600 AU |
| Orbital Period | 3.247 days |
| Mean Orbital Velocity | 149.4 km/s |
| Orbital Eccentricity (e) | 0.06600 |
| Orbital Inclination (i) | 84.9600° |
| Mean Bulk Density | 0.96 g/cm³ (57 km/s vesc) |
| Insolation Flux | 1109.2230 S⊕ (~1,509,653 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 3874.700 LY (1188.000 pc) |