TOI-4427 b
Astrophysical Synthesis & Habitability Characterization
TOI-4427 b is a confirmed gas giant exoplanet orbiting the star TOI-4427, located approximately 646.6 light-years (198.25 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 1.8188% across the stellar disk), this world measures 13.092 Earth radii (1.17 Jupiter radii) and has a measured mass of 87.721 Earth masses (0.28 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.22 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.51 g⊕ (5 m/s²), and an escape velocity of 29 km/s.
In its orbital architecture around TOI-4427, TOI-4427 b completes one full revolution every 4.618 Earth days at a semi-major axis of 0.05389 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 126.9 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.074 carries the world between 0.0499 AU at periapsis and 0.0579 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1040 K (+767°C / +1413°F) and receiving 195.00 S⊕ (~265,395 W/m²), TOI-4427 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-4427 is classified as a stellar host with an effective photospheric temperature of 5,347 K, a radius of 0.89 R☉, a mass of 0.9 M☉, an estimated bolometric luminosity of 0.581 L☉. Stellar evolution modeling indicates an estimated stellar age of 7.9 Gyr and a metallicity of [Fe/H] = 0.002 dex (near-solar heavy-element abundance). From Earth, TOI-4427 shines at apparent V-band magnitude 11.983 (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-4427 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,347 K |
| Stellar Radius | 0.8900 R☉ |
| Stellar Mass | 0.9000 M☉ |
| Bolometric Luminosity | 0.581 L☉ |
| Metallicity [Fe/H] | 0.002 dex |
| Stellar Age | 7.900 Gyr |
| Apparent Magnitude | V: 11.983 · G: 11.859 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.053890 AU |
| Orbital Period | 4.618 days |
| Mean Orbital Velocity | 126.9 km/s |
| Orbital Eccentricity (e) | 0.07400 |
| Orbital Inclination (i) | 87.4000° |
| Mean Bulk Density | 0.22 g/cm³ (29 km/s vesc) |
| Insolation Flux | 195.0000 S⊕ (~265,395 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 646.600 LY (198.251 pc) |