Qatar-5 b
Astrophysical Synthesis & Habitability Characterization
Qatar-5 b is a confirmed gas giant exoplanet orbiting the star Qatar-5, located approximately 1199.1 light-years (367.66 parsecs) from the Solar System. First announced in 2017 by Qatar using the Transit detection technique (producing an estimated primary transit depth of 1.1177% across the stellar disk), this world measures 12.408 Earth radii (1.11 Jupiter radii) and has a measured mass of 1373.026 Earth masses (4.32 Jupiter masses). Combining its mass and radius yields a mean bulk density of 3.96 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 8.92 g⊕ (87.48 m/s²), and an escape velocity of 117.7 km/s.
In its orbital architecture around Qatar-5, Qatar-5 b completes one full revolution every 2.879 Earth days at a semi-major axis of 0.04127 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 155.9 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 1415 K (+1142°C / +2088°F) and receiving 669.00 S⊕ (~910,509 W/m²), Qatar-5 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Qatar-5 is classified as a solar-type yellow star of spectral type G2 V with an effective photospheric temperature of 5,747 K, a radius of 1.076 R☉, a mass of 1.128 M☉, an estimated bolometric luminosity of 1.133 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.53 Gyr and a metallicity of [Fe/H] = 0.377 dex (metal-rich relative to the Sun). From Earth, Qatar-5 shines at apparent V-band magnitude 12.614 (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: Qatar · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | Qatar-5 |
| Spectral Type | G2 V |
| Effective Temp (Teff) | 5,747 K |
| Stellar Radius | 1.0760 R☉ |
| Stellar Mass | 1.1280 M☉ |
| Bolometric Luminosity | 1.133 L☉ |
| Metallicity [Fe/H] | 0.377 dex |
| Stellar Age | 0.530 Gyr |
| Apparent Magnitude | V: 12.614 · G: 12.524 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.041270 AU |
| Orbital Period | 2.879 days |
| Mean Orbital Velocity | 155.9 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 88.7400° |
| Mean Bulk Density | 3.96 g/cm³ (117.7 km/s vesc) |
| Insolation Flux | 669.0000 S⊕ (~910,509 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1199.100 LY (367.658 pc) |