TOI-6420 b
Astrophysical Synthesis & Habitability Characterization
TOI-6420 b is a confirmed gas giant exoplanet orbiting the star TOI-6420, located approximately 2070.2 light-years (634.71 parsecs) from the Solar System. First announced in 2025 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.6959% across the stellar disk), this world measures 11.938 Earth radii (1.07 Jupiter radii) and has a measured mass of 2606.193 Earth masses (8.2 Jupiter masses). Combining its mass and radius yields a mean bulk density of 8.45 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 18.29 g⊕ (179.36 m/s²), and an escape velocity of 165.3 km/s.
In its orbital architecture around TOI-6420, TOI-6420 b completes one full revolution every 6.962 Earth days at a semi-major axis of 0.0753 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 117.7 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.078 carries the world between 0.0694 AU at periapsis and 0.0812 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1213 K (+940°C / +1724°F) and receiving 106.62 S⊕ (~145,108 W/m²), TOI-6420 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-6420 is classified as a stellar host with an effective photospheric temperature of 6,020 K, a radius of 1.312 R☉, a mass of 1.165 M☉, an estimated bolometric luminosity of 2.028 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.4 Gyr and a metallicity of [Fe/H] = 0.24 dex (metal-rich relative to the Sun). From Earth, TOI-6420 shines at apparent V-band magnitude 12.994 (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 | TOI-6420 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,020 K |
| Stellar Radius | 1.3120 R☉ |
| Stellar Mass | 1.1650 M☉ |
| Bolometric Luminosity | 2.028 L☉ |
| Metallicity [Fe/H] | 0.240 dex |
| Stellar Age | 4.400 Gyr |
| Apparent Magnitude | V: 12.994 · G: 12.902 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.075300 AU |
| Orbital Period | 6.962 days |
| Mean Orbital Velocity | 117.7 km/s |
| Orbital Eccentricity (e) | 0.07800 |
| Orbital Inclination (i) | 85.8000° |
| Mean Bulk Density | 8.45 g/cm³ (165.3 km/s vesc) |
| Insolation Flux | 106.6190 S⊕ (~145,108 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2070.200 LY (634.712 pc) |