TOI-2420 b
Astrophysical Synthesis & Habitability Characterization
TOI-2420 b is a confirmed gas giant exoplanet orbiting the star TOI-2420, located approximately 1419.3 light-years (435.17 parsecs) from the Solar System. First announced in 2024 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.3379% across the stellar disk), this world measures 15.02 Earth radii (1.34 Jupiter radii) and has a measured mass of 294.627 Earth masses (0.93 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.48 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.31 g⊕ (12.85 m/s²), and an escape velocity of 49.5 km/s.
In its orbital architecture around TOI-2420, TOI-2420 b completes one full revolution every 5.843 Earth days at a semi-major axis of 0.0684 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 127.4 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.055 carries the world between 0.0646 AU at periapsis and 0.0722 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1572 K (+1299°C / +2370°F) and receiving 1,017.00 S⊕ (~1,384,137 W/m²), TOI-2420 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-2420 is classified as a stellar host with an effective photospheric temperature of 5,707 K, a radius of 2.369 R☉, a mass of 1.158 M☉, an estimated bolometric luminosity of 5.341 L☉. Stellar evolution modeling indicates an estimated stellar age of 5.3 Gyr. From Earth, TOI-2420 shines at apparent V-band magnitude 11.574 (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-2420 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,707 K |
| Stellar Radius | 2.3690 R☉ |
| Stellar Mass | 1.1580 M☉ |
| Bolometric Luminosity | 5.341 L☉ |
| Metallicity [Fe/H] | — |
| Stellar Age | 5.300 Gyr |
| Apparent Magnitude | V: 11.574 · G: 11.286 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.068400 AU |
| Orbital Period | 5.843 days |
| Mean Orbital Velocity | 127.4 km/s |
| Orbital Eccentricity (e) | 0.05500 |
| Orbital Inclination (i) | 82.0700° |
| Mean Bulk Density | 0.48 g/cm³ (49.5 km/s vesc) |
| Insolation Flux | 1017.0000 S⊕ (~1,384,137 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1419.300 LY (435.174 pc) |