TOI-791 c
Astrophysical Synthesis & Habitability Characterization
TOI-791 c 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 0.6484% across the stellar disk), this world measures 12.946 Earth radii (1.15 Jupiter radii) and has a measured mass of 18.6 Earth masses. Combining its mass and radius yields a mean bulk density of 0.05 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.11 g⊕ (1.08 m/s²), and an escape velocity of 13.4 km/s.
In its orbital architecture around TOI-791, TOI-791 c completes one full revolution every 232.016 Earth days at a semi-major axis of 0.863 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 40.5 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.028 (ranging from 0.8388 AU at periapsis to 0.8872 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 363 K (+90°C / +194°F) and receiving 4.12 S⊕ (~5,607 W/m²), TOI-791 c 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 c sharing its stellar neighborhood alongside TOI-791 b.
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) | 0.863000 AU |
| Orbital Period | 232.016 days |
| Mean Orbital Velocity | 40.5 km/s |
| Orbital Eccentricity (e) | 0.02800 |
| Orbital Inclination (i) | 89.6950° |
| Mean Bulk Density | 0.05 g/cm³ (13.4 km/s vesc) |
| Insolation Flux | 4.1200 S⊕ (~5,607 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1112.900 LY (341.221 pc) |