TOI-1181 b
Astrophysical Synthesis & Habitability Characterization
TOI-1181 b is a confirmed gas giant exoplanet orbiting the star TOI-1181, located approximately 987.7 light-years (302.82 parsecs) from the Solar System. First announced in 2022 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.6336% across the stellar disk), this world measures 17.026 Earth radii (1.52 Jupiter radii) and has a measured mass of 374.72 Earth masses (1.18 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.42 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.29 g⊕ (12.65 m/s²), and an escape velocity of 52.5 km/s.
In its orbital architecture around TOI-1181, TOI-1181 b completes one full revolution every 2.103 Earth days at a semi-major axis of 0.0364 AU (an ultra-close orbit less than one-seventh of Mercury's 0.387 AU distance from the Sun, where strong stellar tidal forces typically induce synchronous rotation). Its mean orbital velocity is approximately 188.3 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.011 (ranging from 0.036 AU at periapsis to 0.0368 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1942 K (+1669°C / +3036°F) and receiving 14,140.00 S⊕ (~19,244,540 W/m²), TOI-1181 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-1181 is classified as a warm F-type star of spectral type F9 IV with an effective photospheric temperature of 6,054 K, a radius of 1.961 R☉, a mass of 1.467 M☉, an estimated bolometric luminosity of 4.635 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.7 Gyr and a metallicity of [Fe/H] = 0.38 dex (metal-rich relative to the Sun). From Earth, TOI-1181 shines at apparent V-band magnitude 10.582 (faint and requiring research-grade or CCD telescopic photometry) 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-1181 |
| Spectral Type | F9 IV |
| Effective Temp (Teff) | 6,054 K |
| Stellar Radius | 1.9610 R☉ |
| Stellar Mass | 1.4670 M☉ |
| Bolometric Luminosity | 4.635 L☉ |
| Metallicity [Fe/H] | 0.380 dex |
| Stellar Age | 2.700 Gyr |
| Apparent Magnitude | V: 10.582 · G: 10.478 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.036400 AU |
| Orbital Period | 2.103 days |
| Mean Orbital Velocity | 188.3 km/s |
| Orbital Eccentricity (e) | 0.01100 |
| Orbital Inclination (i) | 87.0000° |
| Mean Bulk Density | 0.42 g/cm³ (52.5 km/s vesc) |
| Insolation Flux | 14140.0000 S⊕ (~19,244,540 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 987.700 LY (302.819 pc) |