NGTS-12 b
Astrophysical Synthesis & Habitability Characterization
NGTS-12 b is a confirmed gas giant exoplanet orbiting the star NGTS-12, located approximately 1456.1 light-years (446.44 parsecs) from the Solar System. First announced in 2020 by Next-Generation Transit Survey (NGTS) using the Transit detection technique (producing an estimated primary transit depth of 0.4594% across the stellar disk), this world measures 11.747 Earth radii (1.05 Jupiter radii) and has a measured mass of 66.109 Earth masses (0.21 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.22 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.48 g⊕ (4.71 m/s²), and an escape velocity of 26.5 km/s.
In its orbital architecture around NGTS-12, NGTS-12 b completes one full revolution every 7.533 Earth days at a semi-major axis of 0.0757 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 109.3 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 1257 K (+984°C / +1803°F) and receiving 416.00 S⊕ (~566,176 W/m²), NGTS-12 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star NGTS-12 is classified as a solar-type yellow star of spectral type G with an effective photospheric temperature of 5,690 K, a radius of 1.589 R☉, a mass of 1.021 M☉, an estimated bolometric luminosity of 2.375 L☉. Stellar evolution modeling indicates an estimated stellar age of 9.4 Gyr and a metallicity of [Fe/H] = -0.03 dex (near-solar heavy-element abundance). From Earth, NGTS-12 shines at apparent V-band magnitude 12.382 (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: Next-Generation Transit Survey (NGTS) · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | NGTS-12 |
| Spectral Type | G |
| Effective Temp (Teff) | 5,690 K |
| Stellar Radius | 1.5890 R☉ |
| Stellar Mass | 1.0210 M☉ |
| Bolometric Luminosity | 2.375 L☉ |
| Metallicity [Fe/H] | -0.030 dex |
| Stellar Age | 9.400 Gyr |
| Apparent Magnitude | V: 12.382 · G: 12.128 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.075700 AU |
| Orbital Period | 7.533 days |
| Mean Orbital Velocity | 109.3 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 88.9000° |
| Mean Bulk Density | 0.22 g/cm³ (26.5 km/s vesc) |
| Insolation Flux | 416.0000 S⊕ (~566,176 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1456.100 LY (446.442 pc) |