TOI-4406 b
Astrophysical Synthesis & Habitability Characterization
TOI-4406 b is a confirmed gas giant exoplanet orbiting the star TOI-4406, located approximately 854 light-years (261.83 parsecs) from the Solar System. First announced in 2023 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.6346% across the stellar disk), this world measures 11.209 Earth radii (1 Jupiter radii) and has a measured mass of 95.349 Earth masses (0.3 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.37 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.76 g⊕ (7.45 m/s²), and an escape velocity of 32.6 km/s.
In its orbital architecture around TOI-4406, TOI-4406 b completes one full revolution every 30.084 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 72.7 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.15 carries the world between 0.1709 AU at periapsis and 0.2312 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 904 K (+631°C / +1168°F) and receiving 58.01 S⊕ (~78,945 W/m²), TOI-4406 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-4406 is classified as a stellar host with an effective photospheric temperature of 6,219 K, a radius of 1.29 R☉, a mass of 1.19 M☉, an estimated bolometric luminosity of 2.233 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.9 Gyr and a metallicity of [Fe/H] = 0.1 dex (metal-rich relative to the Sun). From Earth, TOI-4406 shines at apparent V-band magnitude 10.937 (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-4406 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,219 K |
| Stellar Radius | 1.2900 R☉ |
| Stellar Mass | 1.1900 M☉ |
| Bolometric Luminosity | 2.233 L☉ |
| Metallicity [Fe/H] | 0.100 dex |
| Stellar Age | 2.900 Gyr |
| Apparent Magnitude | V: 10.937 · G: 10.955 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.201000 AU |
| Orbital Period | 30.084 days |
| Mean Orbital Velocity | 72.7 km/s |
| Orbital Eccentricity (e) | 0.15000 |
| Orbital Inclination (i) | 88.4800° |
| Mean Bulk Density | 0.37 g/cm³ (32.6 km/s vesc) |
| Insolation Flux | 58.0054 S⊕ (~78,945 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 854.000 LY (261.834 pc) |