TOI-791 b
Astrophysical Synthesis & Habitability Characterization
TOI-791 b is a confirmed gas giant exoplanet orbiting the star TOI-791, located approximately 1112.9 light-years (341.22 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 0.4793% across the stellar disk), this world measures 11.131 Earth radii (0.99 Jupiter radii) and has a measured mass of 9.5 Earth masses. Combining its mass and radius yields a mean bulk density of 0.04 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.08 g⊕ (0.78 m/s²), and an escape velocity of 10.3 km/s.
In its orbital architecture around TOI-791, TOI-791 b completes one full revolution every 139.299 Earth days at a semi-major axis of 0.602 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 47 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.032 (ranging from 0.5827 AU at periapsis to 0.6213 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 434 K (+161°C / +322°F) and receiving 8.47 S⊕ (~11,528 W/m²), TOI-791 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-791 is classified as a warm F-type star of spectral type F7 with an effective photospheric temperature of 6,294 K, a radius of 1.474 R☉, a mass of 1.28 M☉, an estimated bolometric luminosity of 3.059 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.14 dex (metal-poor relative to the Sun). From Earth, TOI-791 shines at apparent V-band magnitude 11.093 (faint and requiring research-grade or CCD telescopic photometry) in the Southern celestial hemisphere. The TOI-791 system is a multi-planet architecture hosting 2 confirmed worlds, with TOI-791 b sharing its stellar neighborhood alongside TOI-791 c.
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-791 |
| Spectral Type | F7 |
| Effective Temp (Teff) | 6,294 K |
| Stellar Radius | 1.4740 R☉ |
| Stellar Mass | 1.2800 M☉ |
| Bolometric Luminosity | 3.059 L☉ |
| Metallicity [Fe/H] | -0.140 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 11.093 · G: 11.087 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.602000 AU |
| Orbital Period | 139.299 days |
| Mean Orbital Velocity | 47 km/s |
| Orbital Eccentricity (e) | 0.03200 |
| Orbital Inclination (i) | 89.7970° |
| Mean Bulk Density | 0.04 g/cm³ (10.3 km/s vesc) |
| Insolation Flux | 8.4700 S⊕ (~11,528 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1112.900 LY (341.221 pc) |