NGTS-23 b
Astrophysical Synthesis & Habitability Characterization
NGTS-23 b is a confirmed gas giant exoplanet orbiting the star NGTS-23, located approximately 3506 light-years (1074.95 parsecs) from the Solar System. First announced in 2022 by Next-Generation Transit Survey (NGTS) using the Transit detection technique (producing an estimated primary transit depth of 1.1025% across the stellar disk), this world measures 14.202 Earth radii (1.27 Jupiter radii) and has a measured mass of 194.829 Earth masses (0.61 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.38 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.97 g⊕ (9.51 m/s²), and an escape velocity of 41.4 km/s.
In its orbital architecture around NGTS-23, NGTS-23 b completes one full revolution every 4.076 Earth days at a semi-major axis of 0.0504 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 134.5 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 1327 K (+1054°C / +1929°F) and receiving 815.70 S⊕ (~1,110,169 W/m²), NGTS-23 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star NGTS-23 is classified as a warm F-type star of spectral type F9 V with an effective photospheric temperature of 6,057 K, a radius of 1.24 R☉, a mass of 1.01 M☉, an estimated bolometric luminosity of 1.857 L☉. Stellar evolution modeling indicates an estimated stellar age of 6.39 Gyr and a metallicity of [Fe/H] = -0.26 dex (metal-poor relative to the Sun). From Earth, NGTS-23 shines at apparent V-band magnitude 14.126 (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-23 |
| Spectral Type | F9 V |
| Effective Temp (Teff) | 6,057 K |
| Stellar Radius | 1.2400 R☉ |
| Stellar Mass | 1.0100 M☉ |
| Bolometric Luminosity | 1.857 L☉ |
| Metallicity [Fe/H] | -0.260 dex |
| Stellar Age | 6.390 Gyr |
| Apparent Magnitude | V: 14.126 · G: 13.954 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.050400 AU |
| Orbital Period | 4.076 days |
| Mean Orbital Velocity | 134.5 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.1200° |
| Mean Bulk Density | 0.38 g/cm³ (41.4 km/s vesc) |
| Insolation Flux | 815.7013 S⊕ (~1,110,169 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 3506.000 LY (1074.950 pc) |