TOI-808 b
Astrophysical Synthesis & Habitability Characterization
TOI-808 b is a confirmed sub-neptune exoplanet orbiting the star TOI-808, located approximately 320.2 light-years (98.19 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 0.0588% across the stellar disk), this world measures 2.203 Earth radii and has a measured mass of 5.49 Earth masses. Combining its mass and radius yields a mean bulk density of 2.83 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.13 g⊕ (11.08 m/s²), and an escape velocity of 17.7 km/s.
In its orbital architecture around TOI-808, TOI-808 b completes one full revolution every 9.739 Earth days.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 711 K (+438°C / +820°F) and receiving 60.39 S⊕ (~82,188 W/m²), TOI-808 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-808 is classified as a stellar host with an effective photospheric temperature of 5,078 K, a radius of 0.8332 R☉, a mass of 0.87 M☉, an estimated bolometric luminosity of 0.414 L☉. From Earth, TOI-808 shines at apparent V-band magnitude 10.729 (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-808 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,078 K |
| Stellar Radius | 0.8332 R☉ |
| Stellar Mass | 0.8700 M☉ |
| Bolometric Luminosity | 0.414 L☉ |
| Metallicity [Fe/H] | — |
| Stellar Age | — |
| Apparent Magnitude | V: 10.729 · G: 10.603 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | — |
| Orbital Period | 9.739 days |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | 88.4232° |
| Mean Bulk Density | 2.83 g/cm³ (17.7 km/s vesc) |
| Insolation Flux | 60.3881 S⊕ (~82,188 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 320.200 LY (98.185 pc) |