XO-7 b
Astrophysical Synthesis & Habitability Characterization
XO-7 b is a confirmed gas giant exoplanet orbiting the star XO-7, located approximately 763.7 light-years (234.15 parsecs) from the Solar System. First announced in 2019 by XO using the Transit detection technique (producing an estimated primary transit depth of 0.9089% across the stellar disk), this world measures 15.39 Earth radii (1.37 Jupiter radii) and has a measured mass of 225.341 Earth masses (0.71 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.34 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.95 g⊕ (9.32 m/s²), and an escape velocity of 42.8 km/s.
In its orbital architecture around XO-7, XO-7 b completes one full revolution every 2.864 Earth days at a semi-major axis of 0.04421 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 167.9 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.038 (ranging from 0.0425 AU at periapsis to 0.0459 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1743 K (+1470°C / +2678°F) and receiving 1,540.00 S⊕ (~2,095,940 W/m²), XO-7 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star XO-7 is classified as a solar-type yellow star of spectral type G0 V with an effective photospheric temperature of 6,250 K, a radius of 1.48 R☉, a mass of 1.405 M☉, an estimated bolometric luminosity of 2.999 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.18 Gyr and a metallicity of [Fe/H] = 0.432 dex (metal-rich relative to the Sun). From Earth, XO-7 shines at apparent V-band magnitude 10.521 (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: XO · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | XO-7 |
| Spectral Type | G0 V |
| Effective Temp (Teff) | 6,250 K |
| Stellar Radius | 1.4800 R☉ |
| Stellar Mass | 1.4050 M☉ |
| Bolometric Luminosity | 2.999 L☉ |
| Metallicity [Fe/H] | 0.432 dex |
| Stellar Age | 1.180 Gyr |
| Apparent Magnitude | V: 10.521 · G: 10.458 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.044210 AU |
| Orbital Period | 2.864 days |
| Mean Orbital Velocity | 167.9 km/s |
| Orbital Eccentricity (e) | 0.03800 |
| Orbital Inclination (i) | 83.4500° |
| Mean Bulk Density | 0.34 g/cm³ (42.8 km/s vesc) |
| Insolation Flux | 1540.0000 S⊕ (~2,095,940 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 763.700 LY (234.149 pc) |