Qatar-2 b
Astrophysical Synthesis & Habitability Characterization
Qatar-2 b is a confirmed gas giant exoplanet orbiting the star Qatar-2, located approximately 591.6 light-years (181.37 parsecs) from the Solar System. First announced in 2011 by Qatar using the Transit detection technique (producing an estimated primary transit depth of 2.7577% across the stellar disk), this world measures 14.056 Earth radii (1.25 Jupiter radii) and has a measured mass of 792.635 Earth masses (2.49 Jupiter masses). Combining its mass and radius yields a mean bulk density of 1.57 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 4.01 g⊕ (39.32 m/s²), and an escape velocity of 84 km/s.
In its orbital architecture around Qatar-2, Qatar-2 b completes one full revolution every 1.337 Earth days at a semi-major axis of 0.02153 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 175.2 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 1344 K (+1071°C / +1960°F) and receiving 447.41 S⊕ (~608,930 W/m²), Qatar-2 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Qatar-2 is classified as a stellar host with an effective photospheric temperature of 4,645 K, a radius of 0.776 R☉, a mass of 0.743 M☉, an estimated bolometric luminosity of 0.252 L☉. Stellar evolution modeling indicates an estimated stellar age of 5 Gyr and a metallicity of [Fe/H] = 0.02 dex (near-solar heavy-element abundance). From Earth, Qatar-2 shines at apparent V-band magnitude 13.443 (faint and requiring research-grade or CCD telescopic photometry) in the Southern 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: Qatar · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | Qatar-2 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 4,645 K |
| Stellar Radius | 0.7760 R☉ |
| Stellar Mass | 0.7430 M☉ |
| Bolometric Luminosity | 0.252 L☉ |
| Metallicity [Fe/H] | 0.020 dex |
| Stellar Age | 5.000 Gyr |
| Apparent Magnitude | V: 13.443 · G: 13.028 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.021530 AU |
| Orbital Period | 1.337 days |
| Mean Orbital Velocity | 175.2 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 86.1200° |
| Mean Bulk Density | 1.57 g/cm³ (84 km/s vesc) |
| Insolation Flux | 447.4134 S⊕ (~608,930 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 591.600 LY (181.374 pc) |