Kepler-720 b
Astrophysical Synthesis & Habitability Characterization
Kepler-720 b is a confirmed gas giant exoplanet orbiting the star Kepler-720, located approximately 3474.8 light-years (1065.37 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.7024% across the stellar disk), this world measures 8.41 Earth radii (0.75 Jupiter radii) and has a measured mass of 53.4 Earth masses (0.17 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.5 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.76 g⊕ (7.45 m/s²), and an escape velocity of 28.2 km/s.
In its orbital architecture around Kepler-720, Kepler-720 b completes one full revolution every 4.708 Earth days at a semi-major axis of 0.0539 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 124.5 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 1162 K (+889°C / +1632°F) and receiving 384.56 S⊕ (~523,388 W/m²), Kepler-720 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-720 is classified as a stellar host with an effective photospheric temperature of 5,618 K, a radius of 0.92 R☉, a mass of 0.95 M☉, an estimated bolometric luminosity of 0.756 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.63 Gyr and a metallicity of [Fe/H] = 0 dex (near-solar heavy-element abundance). From Earth, Kepler-720 shines at apparent V-band magnitude 15.462 (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-720 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,618 K |
| Stellar Radius | 0.9200 R☉ |
| Stellar Mass | 0.9500 M☉ |
| Bolometric Luminosity | 0.756 L☉ |
| Metallicity [Fe/H] | 0.000 dex |
| Stellar Age | 3.630 Gyr |
| Apparent Magnitude | V: 15.462 · G: 15.164 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.053900 AU |
| Orbital Period | 4.708 days |
| Mean Orbital Velocity | 124.5 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.7100° |
| Mean Bulk Density | 0.5 g/cm³ (28.2 km/s vesc) |
| Insolation Flux | 384.5610 S⊕ (~523,388 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 3474.800 LY (1065.370 pc) |