TOI-4940 b
Astrophysical Synthesis & Habitability Characterization
TOI-4940 b is a confirmed gas giant exoplanet orbiting the star TOI-4940, located approximately 1127.4 light-years (345.66 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 0.2715% across the stellar disk), this world measures 6.61 Earth radii (0.59 Jupiter radii) and has a measured mass of 89 Earth masses (0.28 Jupiter masses). Combining its mass and radius yields a mean bulk density of 1.7 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 2.04 g⊕ (20.01 m/s²), and an escape velocity of 41 km/s.
In its orbital architecture around TOI-4940, TOI-4940 b completes one full revolution every 25.868 Earth days at a semi-major axis of 0.165 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 69.4 km/s (compared to Earth's 29.8 km/s).
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 643 K (+370°C / +698°F) and receiving 40.46 S⊕ (~55,068 W/m²), TOI-4940 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-4940 is classified as a solar-type yellow star of spectral type G8 V with an effective photospheric temperature of 5,504 K, a radius of 1.163 R☉, a mass of 1.012 M☉, an estimated bolometric luminosity of 1.114 L☉. Stellar evolution modeling indicates an estimated stellar age of 9.8 Gyr and a metallicity of [Fe/H] = 0.326 dex (metal-rich relative to the Sun). From Earth, TOI-4940 shines at apparent V-band magnitude 12.448 (faint and requiring research-grade or CCD telescopic photometry) in the Southern 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-4940 |
| Spectral Type | G8 V |
| Effective Temp (Teff) | 5,504 K |
| Stellar Radius | 1.1630 R☉ |
| Stellar Mass | 1.0120 M☉ |
| Bolometric Luminosity | 1.114 L☉ |
| Metallicity [Fe/H] | 0.326 dex |
| Stellar Age | 9.800 Gyr |
| Apparent Magnitude | V: 12.448 · G: 12.304 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.165000 AU |
| Orbital Period | 25.868 days |
| Mean Orbital Velocity | 69.4 km/s |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | 88.4700° |
| Mean Bulk Density | 1.7 g/cm³ (41 km/s vesc) |
| Insolation Flux | 40.4612 S⊕ (~55,068 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1127.400 LY (345.659 pc) |