NGTS-11 b
Astrophysical Synthesis & Habitability Characterization
NGTS-11 b is a confirmed gas giant exoplanet orbiting the star NGTS-11, located approximately 621.1 light-years (190.42 parsecs) from the Solar System. First announced in 2020 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 1.0183% across the stellar disk), this world measures 9.158 Earth radii (0.82 Jupiter radii) and has a measured mass of 109.334 Earth masses (0.34 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.78 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.3 g⊕ (12.75 m/s²), and an escape velocity of 38.7 km/s.
In its orbital architecture around NGTS-11, NGTS-11 b completes one full revolution every 35.455 Earth days at a semi-major axis of 0.201 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 61.7 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.13 carries the world between 0.1749 AU at periapsis and 0.2271 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 435 K (+162°C / +324°F) and receiving 9.24 S⊕ (~12,578 W/m²), NGTS-11 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star NGTS-11 is classified as an orange K-type star of spectral type K with an effective photospheric temperature of 5,050 K, a radius of 0.832 R☉, a mass of 0.862 M☉, an estimated bolometric luminosity of 0.404 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.9 Gyr and a metallicity of [Fe/H] = 0.22 dex (metal-rich relative to the Sun). From Earth, NGTS-11 shines at apparent V-band magnitude 12.456 (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: Transiting Exoplanet Survey Satellite (TESS) · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | NGTS-11 |
| Spectral Type | K |
| Effective Temp (Teff) | 5,050 K |
| Stellar Radius | 0.8320 R☉ |
| Stellar Mass | 0.8620 M☉ |
| Bolometric Luminosity | 0.404 L☉ |
| Metallicity [Fe/H] | 0.220 dex |
| Stellar Age | 3.900 Gyr |
| Apparent Magnitude | V: 12.456 · G: 12.190 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.201000 AU |
| Orbital Period | 35.455 days |
| Mean Orbital Velocity | 61.7 km/s |
| Orbital Eccentricity (e) | 0.13000 |
| Orbital Inclination (i) | 89.1600° |
| Mean Bulk Density | 0.78 g/cm³ (38.7 km/s vesc) |
| Insolation Flux | 9.2420 S⊕ (~12,578 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 621.100 LY (190.422 pc) |