TOI-5108 b
Astrophysical Synthesis & Habitability Characterization
TOI-5108 b is a confirmed gas giant exoplanet orbiting the star TOI-5108, located approximately 427 light-years (130.92 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 0.22% across the stellar disk), this world measures 6.6 Earth radii (0.59 Jupiter radii) and has a measured mass of 32 Earth masses (0.1 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.61 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.73 g⊕ (7.16 m/s²), and an escape velocity of 24.6 km/s.
In its orbital architecture around TOI-5108, TOI-5108 b completes one full revolution every 6.754 Earth days at a semi-major axis of 0.073 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 117.6 km/s (compared to Earth's 29.8 km/s).
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1180 K (+907°C / +1665°F) and receiving 122.79 S⊕ (~167,110 W/m²), TOI-5108 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-5108 is classified as a stellar host with an effective photospheric temperature of 5,808 K, a radius of 1.29 R☉, a mass of 1.1 M☉, an estimated bolometric luminosity of 1.699 L☉. Stellar evolution modeling indicates an estimated stellar age of 5.8 Gyr and a metallicity of [Fe/H] = 0.2 dex (metal-rich relative to the Sun). From Earth, TOI-5108 shines at apparent V-band magnitude 9.75 (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-5108 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,808 K |
| Stellar Radius | 1.2900 R☉ |
| Stellar Mass | 1.1000 M☉ |
| Bolometric Luminosity | 1.699 L☉ |
| Metallicity [Fe/H] | 0.200 dex |
| Stellar Age | 5.800 Gyr |
| Apparent Magnitude | V: 9.750 · G: 9.608 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.073000 AU |
| Orbital Period | 6.754 days |
| Mean Orbital Velocity | 117.6 km/s |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | 85.9100° |
| Mean Bulk Density | 0.61 g/cm³ (24.6 km/s vesc) |
| Insolation Flux | 122.7850 S⊕ (~167,110 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 427.000 LY (130.919 pc) |