V0391 Peg b
Astrophysical Synthesis & Habitability Characterization
V0391 Peg b is a confirmed gas giant exoplanet orbiting the star V0391 Peg, located approximately 3900.8 light-years (1195.98 parsecs) from the Solar System. First announced in 2007 by Multiple Observatories using the Pulsation Timing Variations detection technique, this world measures 13.1 Earth radii (1.17 Jupiter radii) and has a measured mass of 1017.056 Earth masses (3.2 Jupiter masses). Combining its mass and radius yields a mean bulk density of 2.49 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 5.93 g⊕ (58.15 m/s²), and an escape velocity of 98.6 km/s.
In its orbital architecture around V0391 Peg, V0391 Peg b completes one full revolution every 1170 Earth days (3.2Julian years) at a semi-major axis of 1.7 AU (corresponding to the middle-system regime between Mars at 1.52 AU and Jupiter at 5.20 AU). Its mean orbital velocity is approximately 15.8 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 520 K (+247°C / +477°F) and receiving 9.38 S⊕ (~12,759 W/m²), V0391 Peg b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star V0391 Peg is classified as a catalogued stellar host of spectral type sdBV with an effective photospheric temperature of 29,300 K, a radius of 0.23 R☉, a mass of 0.5 M☉, an estimated bolometric luminosity of 34.98 L☉. Stellar evolution modeling indicates an estimated stellar age of 10 Gyr. From Earth, V0391 Peg shines at apparent V-band magnitude 14.769 (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: Multiple Observatories · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | V0391 Peg |
| Spectral Type | sdBV |
| Effective Temp (Teff) | 29,300 K |
| Stellar Radius | 0.2300 R☉ |
| Stellar Mass | 0.5000 M☉ |
| Bolometric Luminosity | 34.98 L☉ |
| Metallicity [Fe/H] | — |
| Stellar Age | 10.000 Gyr |
| Apparent Magnitude | V: 14.769 · G: 14.590 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 1.700000 AU |
| Orbital Period | 1170 days |
| Mean Orbital Velocity | 15.8 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 2.49 g/cm³ (98.6 km/s vesc) |
| Insolation Flux | 9.3750 S⊕ (~12,759 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 3900.800 LY (1195.980 pc) |