TOI-799 b
Astrophysical Synthesis & Habitability Characterization
TOI-799 b is a confirmed sub-neptune exoplanet orbiting the star TOI-799, located approximately 517 light-years (158.53 parsecs) from the Solar System. First announced in 2026 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.0428% across the stellar disk), this world measures 2.066 Earth radii and has a measured mass of 4.92 Earth masses. Combining its mass and radius yields a mean bulk density of 3.08 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.15 g⊕ (11.28 m/s²), and an escape velocity of 17.3 km/s.
In its orbital architecture around TOI-799, TOI-799 b completes one full revolution every 5.545 Earth days.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 959 K (+686°C / +1267°F) and receiving 199.63 S⊕ (~271,700 W/m²), TOI-799 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-799 is classified as a stellar host with an effective photospheric temperature of 5,663 K, a radius of 0.9155 R☉, a mass of 1 M☉, an estimated bolometric luminosity of 0.773 L☉. From Earth, TOI-799 shines at apparent V-band magnitude 11.195 (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-799 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,663 K |
| Stellar Radius | 0.9155 R☉ |
| Stellar Mass | 1.0000 M☉ |
| Bolometric Luminosity | 0.773 L☉ |
| Metallicity [Fe/H] | — |
| Stellar Age | — |
| Apparent Magnitude | V: 11.195 · G: 11.056 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | — |
| Orbital Period | 5.545 days |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | 87.7697° |
| Mean Bulk Density | 3.08 g/cm³ (17.3 km/s vesc) |
| Insolation Flux | 199.6326 S⊕ (~271,700 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 517.000 LY (158.526 pc) |