TOI-5181 A b
Astrophysical Synthesis & Habitability Characterization
TOI-5181 A b is a confirmed gas giant exoplanet orbiting the star TOI-5181 A, located approximately 1566.1 light-years (480.16 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 0.6399% across the stellar disk), this world measures 13.35 Earth radii (1.19 Jupiter radii) and has a measured mass of 330.542 Earth masses (1.04 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.77 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.85 g⊕ (18.14 m/s²), and an escape velocity of 55.7 km/s.
In its orbital architecture around TOI-5181 A, TOI-5181 A b completes one full revolution every 3.892 Earth days at a semi-major axis of 0.0522 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 145.9 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.15 carries the world between 0.0444 AU at periapsis and 0.06 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1585 K (+1312°C / +2394°F) and receiving 1,053.00 S⊕ (~1,433,133 W/m²), TOI-5181 A b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-5181 A is classified as a stellar host with an effective photospheric temperature of 6,060 K, a radius of 1.53 R☉, a mass of 1.25 M☉, an estimated bolometric luminosity of 2.832 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.1 Gyr and a metallicity of [Fe/H] = 0.208 dex (metal-rich relative to the Sun). From Earth, TOI-5181 A shines at apparent V-band magnitude 12.301 (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-5181 A |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,060 K |
| Stellar Radius | 1.5300 R☉ |
| Stellar Mass | 1.2500 M☉ |
| Bolometric Luminosity | 2.832 L☉ |
| Metallicity [Fe/H] | 0.208 dex |
| Stellar Age | 4.100 Gyr |
| Apparent Magnitude | V: 12.301 · G: 12.219 |
| System Architecture | 2 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.052200 AU |
| Orbital Period | 3.892 days |
| Mean Orbital Velocity | 145.9 km/s |
| Orbital Eccentricity (e) | 0.15000 |
| Orbital Inclination (i) | 83.6800° |
| Mean Bulk Density | 0.77 g/cm³ (55.7 km/s vesc) |
| Insolation Flux | 1053.0000 S⊕ (~1,433,133 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1566.100 LY (480.155 pc) |