TOI-3474 b
Astrophysical Synthesis & Habitability Characterization
TOI-3474 b is a confirmed gas giant exoplanet orbiting the star TOI-3474, located approximately 1370.3 light-years (420.12 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 1.1471% across the stellar disk), this world measures 14.673 Earth radii (1.31 Jupiter radii) and has a measured mass of 193.875 Earth masses (0.61 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.34 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.9 g⊕ (8.83 m/s²), and an escape velocity of 40.7 km/s.
In its orbital architecture around TOI-3474, TOI-3474 b completes one full revolution every 3.88 Earth days at a semi-major axis of 0.0502 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 140.8 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.13 carries the world between 0.0437 AU at periapsis and 0.0567 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1451 K (+1178°C / +2152°F) and receiving 740.00 S⊕ (~1,007,140 W/m²), TOI-3474 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-3474 is classified as a stellar host with an effective photospheric temperature of 6,020 K, a radius of 1.256 R☉, a mass of 1.121 M☉, an estimated bolometric luminosity of 1.859 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.7 Gyr and a metallicity of [Fe/H] = 0.146 dex (metal-rich relative to the Sun). From Earth, TOI-3474 shines at apparent V-band magnitude 12.531 (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-3474 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,020 K |
| Stellar Radius | 1.2560 R☉ |
| Stellar Mass | 1.1210 M☉ |
| Bolometric Luminosity | 1.859 L☉ |
| Metallicity [Fe/H] | 0.146 dex |
| Stellar Age | 4.700 Gyr |
| Apparent Magnitude | V: 12.531 · G: 12.442 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.050200 AU |
| Orbital Period | 3.88 days |
| Mean Orbital Velocity | 140.8 km/s |
| Orbital Eccentricity (e) | 0.13000 |
| Orbital Inclination (i) | 89.3300° |
| Mean Bulk Density | 0.34 g/cm³ (40.7 km/s vesc) |
| Insolation Flux | 740.0000 S⊕ (~1,007,140 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1370.300 LY (420.123 pc) |