TOI-4633 c
Astrophysical Synthesis & Habitability Characterization
TOI-4633 c is a confirmed sub-neptune exoplanet orbiting the star TOI-4633, located approximately 310.5 light-years (95.2 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 0.0781% across the stellar disk), this world measures 3.2 Earth radii (0.29 Jupiter radii) and has a measured mass of 123 Earth masses (0.39 Jupiter masses). Combining its mass and radius yields a mean bulk density of 20.7 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 12.01 g⊕ (117.78 m/s²), and an escape velocity of 69.4 km/s.
In its orbital architecture around TOI-4633, TOI-4633 c completes one full revolution every 271.945 Earth days at a semi-major axis of 0.847 AU (comparable to the inner terrestrial zone between Venus, Earth at 1.00 AU, and Mars at 1.52 AU). Its mean orbital velocity is approximately 33.9 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.117 carries the world between 0.7479 AU at periapsis and 0.9461 AU at apoapsis, driving measurable seasonal insolation cycles.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 3.200 R⊕, TOI-4633 c exceeds the empirical ~1.8–2.2 R⊕ Fulton radius valley threshold, indicating a substantial hydrogen-helium or supercritical volatile envelope without a conventional solid terrestrial surface.
The host star TOI-4633 is classified as a solar-type yellow star of spectral type G V with an effective photospheric temperature of 5,800 K, a radius of 1.05 R☉, a mass of 1.1 M☉, an estimated bolometric luminosity of 1.119 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.3 Gyr and a metallicity of [Fe/H] = 0.238 dex (metal-rich relative to the Sun). From Earth, TOI-4633 shines at apparent V-band magnitude 9.017 (accessible to binoculars and small amateur telescopes) in the Northern 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-4633 |
| Spectral Type | G V |
| Effective Temp (Teff) | 5,800 K |
| Stellar Radius | 1.0500 R☉ |
| Stellar Mass | 1.1000 M☉ |
| Bolometric Luminosity | 1.119 L☉ |
| Metallicity [Fe/H] | 0.238 dex |
| Stellar Age | 1.300 Gyr |
| Apparent Magnitude | V: 9.017 · G: 8.820 |
| System Architecture | 2 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.847000 AU |
| Orbital Period | 271.945 days |
| Mean Orbital Velocity | 33.9 km/s |
| Orbital Eccentricity (e) | 0.11700 |
| Orbital Inclination (i) | 89.8880° |
| Mean Bulk Density | 20.7 g/cm³ (69.4 km/s vesc) |
| Insolation Flux | 1.5600 S⊕ (~2,123 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 310.500 LY (95.202 pc) |