TOI-333 b
Astrophysical Synthesis & Habitability Characterization
TOI-333 b is a confirmed sub-neptune exoplanet orbiting the star TOI-333, located approximately 1148.9 light-years (352.27 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 0.1261% across the stellar disk), this world measures 4.26 Earth radii (0.38 Jupiter radii) and has a measured mass of 20.1 Earth masses. Combining its mass and radius yields a mean bulk density of 1.43 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.11 g⊕ (10.89 m/s²), and an escape velocity of 24.3 km/s.
In its orbital architecture around TOI-333, TOI-333 b completes one full revolution every 3.785 Earth days at a semi-major axis of 0.049 AU (an ultra-close orbit less than one-seventh of Mercury's 0.387 AU distance from the Sun, where strong stellar tidal forces typically induce synchronous rotation). Its mean orbital velocity is approximately 140.8 km/s (compared to Earth's 29.8 km/s). The orbit is modeled as circular (e = 0.00), maintaining a constant stellar distance throughout its year.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1445 K (+1172°C / +2142°F) and receiving 650.50 S⊕ (~885,325 W/m²), TOI-333 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-333 is classified as a stellar host with an effective photospheric temperature of 6,241 K, a radius of 1.1 R☉, a mass of 1.2 M☉, an estimated bolometric luminosity of 1.647 L☉. Stellar evolution modeling indicates an estimated stellar age of 1 Gyr and a metallicity of [Fe/H] = 0.01 dex (near-solar heavy-element abundance). From Earth, TOI-333 shines at apparent V-band magnitude 12.205 (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-333 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,241 K |
| Stellar Radius | 1.1000 R☉ |
| Stellar Mass | 1.2000 M☉ |
| Bolometric Luminosity | 1.647 L☉ |
| Metallicity [Fe/H] | 0.010 dex |
| Stellar Age | 1.000 Gyr |
| Apparent Magnitude | V: 12.205 · G: 11.899 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.049000 AU |
| Orbital Period | 3.785 days |
| Mean Orbital Velocity | 140.8 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.2600° |
| Mean Bulk Density | 1.43 g/cm³ (24.3 km/s vesc) |
| Insolation Flux | 650.4959 S⊕ (~885,325 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1148.900 LY (352.269 pc) |