PH2 b
Astrophysical Synthesis & Habitability Characterization
PH2 b is a confirmed gas giant exoplanet orbiting the star PH2, located approximately 1121.5 light-years (343.86 parsecs) from the Solar System. First announced in 2013 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.8136% across the stellar disk), this world measures 9.337 Earth radii (0.83 Jupiter radii) and has a measured mass of 87.085 Earth masses (0.27 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.59 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1 g⊕ (9.81 m/s²), and an escape velocity of 34.2 km/s.
In its orbital architecture around PH2, PH2 b completes one full revolution every 282.525 Earth days at a semi-major axis of 0.833 AU (comparable to the inner terrestrial zone between Venus, Earth at 1.00 AU, and Mars at 1.52 AU). Its mean orbital velocity is approximately 32.1 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.215 carries the world between 0.6539 AU at periapsis and 1.0121 AU at apoapsis, driving measurable seasonal insolation cycles.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 9.337 R⊕, PH2 b exceeds the empirical ~1.8–2.2 R⊕ Fulton radius valley threshold, indicating a substantial hydrogen-helium or supercritical volatile envelope without a conventional solid terrestrial surface.
The host star PH2 is classified as a solar-type yellow star of spectral type G3 with an effective photospheric temperature of 5,734 K, a radius of 0.949 R☉, a mass of 0.966 M☉, an estimated bolometric luminosity of 0.873 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.1 Gyr and a metallicity of [Fe/H] = 0.017 dex (near-solar heavy-element abundance). From Earth, PH2 shines at apparent V-band magnitude 12.645 (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 | PH2 |
| Spectral Type | G3 |
| Effective Temp (Teff) | 5,734 K |
| Stellar Radius | 0.9490 R☉ |
| Stellar Mass | 0.9660 M☉ |
| Bolometric Luminosity | 0.873 L☉ |
| Metallicity [Fe/H] | 0.017 dex |
| Stellar Age | 4.100 Gyr |
| Apparent Magnitude | V: 12.645 · G: 12.581 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.833000 AU |
| Orbital Period | 282.525 days |
| Mean Orbital Velocity | 32.1 km/s |
| Orbital Eccentricity (e) | 0.21500 |
| Orbital Inclination (i) | 89.8980° |
| Mean Bulk Density | 0.59 g/cm³ (34.2 km/s vesc) |
| Insolation Flux | 1.2000 S⊕ (~1,633 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1121.500 LY (343.863 pc) |