TOI-470 b
Astrophysical Synthesis & Habitability Characterization
TOI-470 b is a confirmed sub-neptune exoplanet orbiting the star TOI-470, located approximately 425.5 light-years (130.46 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 0.2293% across the stellar disk), this world measures 4.34 Earth radii (0.39 Jupiter radii) and has a measured mass of 17.4 Earth masses. Combining its mass and radius yields a mean bulk density of 1.17 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.92 g⊕ (9.02 m/s²), and an escape velocity of 22.4 km/s.
In its orbital architecture around TOI-470, TOI-470 b completes one full revolution every 12.191 Earth days at a semi-major axis of 0.119 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 106.2 km/s (compared to Earth's 29.8 km/s).
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 660 K (+387°C / +729°F) and receiving 44.76 S⊕ (~60,912 W/m²), TOI-470 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-470 is classified as a solar-type yellow star of spectral type G with an effective photospheric temperature of 5,190 K, a radius of 0.831 R☉, a mass of 0.87 M☉, an estimated bolometric luminosity of 0.45 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.4 Gyr and a metallicity of [Fe/H] = 0.1 dex (metal-rich relative to the Sun). From Earth, TOI-470 shines at apparent V-band magnitude 11.171 (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-470 |
| Spectral Type | G |
| Effective Temp (Teff) | 5,190 K |
| Stellar Radius | 0.8310 R☉ |
| Stellar Mass | 0.8700 M☉ |
| Bolometric Luminosity | 0.45 L☉ |
| Metallicity [Fe/H] | 0.100 dex |
| Stellar Age | 1.400 Gyr |
| Apparent Magnitude | V: 11.171 · G: 11.246 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.119000 AU |
| Orbital Period | 12.191 days |
| Mean Orbital Velocity | 106.2 km/s |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | 89.5270° |
| Mean Bulk Density | 1.17 g/cm³ (22.4 km/s vesc) |
| Insolation Flux | 44.7551 S⊕ (~60,912 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 425.500 LY (130.460 pc) |